{"id":40520,"date":"2023-01-02T21:27:07","date_gmt":"2023-01-02T12:27:07","guid":{"rendered":"https:\/\/kinsta.com\/jp\/?p=40520&post_type=knowledgebase&preview_id=40520"},"modified":"2025-10-02T04:47:36","modified_gmt":"2025-10-01T19:47:36","slug":"uncaught-typeerror-cannot-read-property","status":"publish","type":"post","link":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/","title":{"rendered":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5"},"content":{"rendered":"

\u3069\u306e\u3088\u3046\u306a\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u8a00\u8a9e<\/a>\u3067\u3042\u3063\u3066\u3082\u3001\u7fd2\u5f97\u4e2d\u3084\u4f7f\u7528\u6642\u306b\u306f\u5fc5\u305a\u30a8\u30e9\u30fc\u306b\u906d\u9047\u3059\u308b\u3082\u306e\u3002\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u306f\u901a\u5e38\u3001\u30b3\u30fc\u30c9\u554f\u984c\u3092\u7279\u5b9a\u3059\u308b\u306e\u306b\u5f79\u7acb\u3061\u307e\u3059\u3002<\/p>\n

\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u306f\u3001\u308f\u304b\u308a\u3084\u3059\u3044\u3082\u306e\u304b\u3089\u3001\u7406\u89e3\u3057\u96e3\u3044\u3082\u306e\u307e\u3067\u3055\u307e\u3056\u307e\u3067\u3059\u3002<\/p>\n\n

\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u6700\u3082\u4e00\u822c\u7684\u306aJavaScript\u306e\u30a8\u30e9\u30fc\u306e1\u3064\u3067\u3042\u308b\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u306b\u3064\u3044\u3066\u6398\u308a\u4e0b\u3052\u307e\u3059\u3002<\/p>\n

\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u306e\u610f\u5473\u3001\u4e3b\u306a\u539f\u56e0\u3001\u305d\u3057\u3066\u89e3\u6c7a\u7b56\u3092\u9806\u306b\u89e3\u8aac\u3057\u3066\u3044\u304d\u307e\u3059\u306e\u3067\u3001\u305c\u3072\u6700\u5f8c\u307e\u3067\u3054\u89a7\u304f\u3060\u3055\u3044\u3002<\/p>\n

<\/div><\/kinsta-auto-toc>\n

JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3068\u306f<\/h2>\n

\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u306f\u3001undefined<\/code>\u5909\u6570\u3092\u4f7f\u7528\u307e\u305f\u306f\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3057\u305f\u3068\u304d\u306b\u767a\u751f\u3059\u308b\u306e\u304c\u901a\u4f8b\u3067\u3059\u3002Vanilla JS\u306a\u3069\u3001\u4efb\u610f\u306eJavascript\u30d5\u30ec\u30fc\u30e0\u30ef\u30fc\u30af<\/a>\u3067\u898b\u3089\u308c\u307e\u3059\u3002<\/p>\n

Chrome\u306e\u30c7\u30d9\u30ed\u30c3\u30d1\u30fc \u30c4\u30fc\u30eb\u3084Kinsta\u306e\u30ef\u30f3\u30af\u30ea\u30c3\u30af\u30b9\u30c6\u30fc\u30b8\u30f3\u30b0\u74b0\u5883\u6a5f\u80fd<\/a>\u306a\u3069\u3001\u958b\u767a\u30c4\u30fc\u30eb\u3092\u4f7f\u7528\u3059\u308c\u3070\u3001\u30a8\u30e9\u30fc\u306e\u691c\u51fa\u3084\u30b3\u30fc\u30c9\u306e\u30c6\u30b9\u30c8\u306a\u3069\u3001\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u4e2d\u306b\u7d20\u65e9\u304f\u30a8\u30e9\u30fc\u306b\u5bfe\u51e6\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n

JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u306e\u539f\u56e0\u3068\u89e3\u6c7a\u7b56<\/h2>\n

\u305d\u308c\u3067\u306f\u65e9\u901f\u3001JavaScript<\/a>\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u306e\u539f\u56e0\u3068\u89e3\u6c7a\u65b9\u6cd5\u306b\u3064\u3044\u3066\u3001\u30b3\u30fc\u30c9\u4f8b\u3092\u7528\u3044\u306a\u304c\u3089\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n

\u672a\u5b9a\u7fa9\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b<\/h3>\n

\u307e\u305a\u8003\u3048\u3089\u308c\u308b\u306e\u306f\u3001\u672a\u5b9a\u7fa9\uff08undefined\uff09\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3057\u3066\u3044\u308b\u3053\u3068\u3002<\/p>\n

\u4f8b\u3092\u898b\u3066\u307f\u307e\u3059\u3002<\/p>\n

let person;<\/code><\/pre>\n
\u4e0a\u306e\u30b3\u30fc\u30c9\u306f\u3001person<\/code>\u3068\u3044\u3046\u5909\u6570\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002\u3053\u306e\u5909\u6570\u3092name<\/code>\u3001age<\/code>\u3001hobby<\/code>\u306e\u3088\u3046\u306a\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u6301\u3064\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u3059\u308b\u3068\u3057\u307e\u3059\u3002<\/p>\n
\u3057\u304b\u3057\u3001\u3053\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u4f5c\u6210\u3057\u3066\u304a\u3089\u305a\u3001\u305d\u308c\u3092\u5fd8\u308c\u3066\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3059\u308b\u3068\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u30a8\u30e9\u30fc<\/a>\u304c\u767a\u751f\u3057\u307e\u3059\u3002<\/p>\n
let person;\nconsole.log(person.name);\n\/\/ Uncaught TypeError: Cannot read properties of undefined (reading 'name')<\/code><\/pre>\n
\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3057\u305fname<\/code>\u30d7\u30ed\u30d1\u30c6\u30a3\u304c\u5b58\u5728\u3057\u306a\u3044\u305f\u3081\u3001\u300cUncaught TypeError:Uncaught TypeError: Cannot read properties of undefined (reading ‘name’)\u300d\u3068\u3044\u3046\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8fd4\u3055\u308c\u307e\u3059\u3002<\/p>\n
\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3078\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u306e\u4f5c\u6210\u3084\u8ffd\u52a0\u3092\u5fd8\u308c\u3066\u3057\u307e\u3046\u306e\u306f\u3001\u3088\u304f\u3042\u308b\u3053\u3068\u3067\u3059\u3002<\/p>\n
\u30a8\u30e9\u30fc\u3092\u4fee\u6b63\u3059\u308b\u306b\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u3044\u304f\u3064\u304b\u8ffd\u52a0\u3057\u3066\u307f\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n
let person = {\n  name: \"John\",\n  age: 200,\n  hobby: \"coding\"\n}\nconsole.log(person.name);\n\/\/ John<\/code><\/pre>\n
\u4e0a\u8a18\u306f\u3001name<\/code>\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u8ffd\u52a0\u3057\u3001\u30a2\u30af\u30bb\u30b9\u3059\u308b\u3068\u300cJohn\u300d\u3068\u3044\u3046\u5024\u304c\u8fd4\u3055\u308c\u308b\u30b3\u30fc\u30c9\u3067\u3059\u3002<\/p>\n
\u914d\u5217\u306b\u5b58\u5728\u3057\u306a\u3044\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b<\/h3>\n
\u5148\u307b\u3069\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3068\u540c\u69d8\u306b\u3001\u307e\u3060\u521d\u671f\u5316\u3055\u308c\u3066\u3044\u306a\u3044\u914d\u5217\u306e\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3057\u3066\u3082\u3001\u3053\u306e\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3057\u307e\u3059\u3002<\/p>\n
\u4ee5\u4e0b\u306f\u305d\u306e\u4f8b\u3067\u3059\u3002<\/p>\n
let arr;\nconsole.log(arr[0]);\n\/\/ Uncaught TypeError: Cannot read properties of undefined (reading '0')<\/code><\/pre>\n
\u3053\u308c\u306f\u3001arr<\/code>\u3068\u3044\u3046\u914d\u5217\u306e\u6700\u521d\u306e\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u30b3\u30fc\u30c9\u3002<\/p>\n
\u3053\u306e\u914d\u5217\u306f\u5ba3\u8a00\u3055\u308c\u3066\u3044\u308b\u3082\u306e\u306e\u3001\u521d\u671f\u5316\u3055\u308c\u3066\u3044\u307e\u305b\u3093\u3002\u3064\u307e\u308a\u3001\u307e\u3060\u3069\u306e\u8981\u7d20\u3082\u5272\u308a\u5f53\u3066\u3089\u308c\u3066\u3044\u306a\u3044\u3053\u3068\u3092\u610f\u5473\u3057\u307e\u3059\u3002<\/p>\n
\u3053\u308c\u3092\u89e3\u6c7a\u3059\u308b\u306b\u306f\u3001\u4f8b\u3048\u3070\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u3001\u30a2\u30af\u30bb\u30b9\u3059\u308b\u524d\u306b\u914d\u5217\u8981\u7d20\u3092\u8ffd\u52a0\u3057\u3066\u304a\u304d\u307e\u3059\u3002<\/p>\n
let arr = [2,4,6,8]\nconsole.log(arr[0]);\n\/\/ 2<\/code><\/pre>\n
\u5b58\u5728\u3057\u306a\u3044DOM\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b<\/h3>\n
JavaScript\u3067DOM\uff08\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u30e2\u30c7\u30eb\uff09\u3092\u64cd\u4f5c\u3057\u3066\u3044\u308b\u969b\u306b\u3082\u3001\u300cUncaught TypeError: Cannot read properties\u300d\u30a8\u30e9\u30fc\u306b\u906d\u9047\u3059\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n
\u539f\u56e0\u3068\u3057\u3066\u306f\u3001DOM\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\u969b\u306e\u30b9\u30da\u30eb\u30df\u30b9\u3001\u30a2\u30af\u30bb\u30b9\u3057\u305f\u3044\u8981\u7d20\u304c\u5b58\u5728\u3057\u306a\u3044\u3001DOM\u304c\u8aad\u307f\u8fbc\u307e\u308c\u308b\u524d\u306b\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3088\u3046\u3068\u3057\u3066\u3044\u308b\uff08\u3053\u308c\u306b\u3064\u3044\u3066\u306f\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\uff09\u306a\u3069\u304c\u8003\u3048\u3089\u308c\u307e\u3059\u3002<\/p>\n
\u4ee5\u4e0b\u3001\u5b58\u5728\u3057\u306a\u3044DOM\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3057\u3001\u300cUncaught TypeError: Cannot read properties\u300d\u30a8\u30e9\u30fc\u304c\u8fd4\u3055\u308c\u308b\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
HTML\u30b3\u30fc\u30c9\u306f\u4ee5\u4e0b\u306e\u901a\u308a\u3002<\/p>\n
<!DOCTYPE html>\n<html>\n  <head>\n    <title>Error Tutorial<\/title>\n  <\/head>\n  <body>\n    <h1 id=\"content\">Hello World!<\/h1>\n    <script src=\"app.js\"><\/script>\n  <\/body>\n<\/html><\/code><\/pre>\n
\u3053\u308c\u306f\u3001\u57fa\u672c\u7684\u306aHTML\u6587\u66f8\u3092\u4f5c\u6210\u3057\u3001ID\u304c\u300ccontent\u300d\u3067\u3042\u308bh1<\/code>\u8981\u7d20\u3092\u4f5c\u6210\u3059\u308b\u30b3\u30fc\u30c9\u3067\u3059\u3002<\/p>\n
JavaScript\u306e\u30b3\u30fc\u30c9\u306f\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
let content = document.getElementById(\"constent\");\nconsole.log(content.textContent);\n\/\/ Uncaught TypeError: Cannot read properties of null (reading 'textContent');<\/code><\/pre>\n
\u3059\u3079\u3066\u6b63\u3057\u304f\u5b9f\u884c\u3057\u305f\u3088\u3046\u306b\u898b\u3048\u307e\u3059\u304c\u3001\u30a8\u30e9\u30fc\u304c\u8fd4\u3063\u3066\u304d\u307e\u3059\u3002<\/p>\n
\u4e9b\u7d30\u306a\u70b9\u3067\u3059\u304c\u3001h1<\/code>\u8981\u7d20\u306eID\u3092\u53d6\u5f97\u3059\u308b\u306e\u306b\u300ccontent\u300d\u3092\u300cconstent\u300d\u3068\u30b9\u30da\u30eb\u30df\u30b9\u3057\u3066\u3044\u308b\u306e\u304c\u539f\u56e0\u3067\u3059\u3002<\/p>\n
document.getElementById(\"content<\/strong>\");<\/code>\u3067\u306f\u306a\u304f\u3001document.getElementById(\"constent<\/strong>\");<\/code>\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n
DOM\u306b\u307e\u3060\u4f5c\u6210\u3055\u308c\u3066\u3044\u306a\u3044ID\u3084\u30af\u30e9\u30b9\u540d\u3092\u53d6\u5f97\u3057\u3088\u3046\u3068\u3057\u3066\u3082\u3001\u540c\u3058\u30a8\u30e9\u30fc\u304c\u767a\u751f\u3057\u307e\u3059\u3002<\/p>\n
\u3053\u308c\u3092\u89e3\u6c7a\u3059\u308b\u306b\u306f\u3001\u30b9\u30da\u30eb\u30df\u30b9\u3092\u4fee\u6b63\u3059\u308b\u304b\u3001\u30a2\u30af\u30bb\u30b9\u3057\u305f\u3044\u8981\u7d20\u304cDOM\u306b\u5b58\u5728\u3057\u3066\u3044\u308b\u304b\u3092\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n
Body\u30bf\u30b0\u5185\u306e\u4ed6\u306eDOM\u8981\u7d20\u4e0a\u306bScript\u8981\u7d20\u3092\u914d\u7f6e<\/h3>\n
script<\/code>\u8981\u7d20\u306e\u4f4d\u7f6e\u306f\u3001JavaScript\u306e\u30b3\u30fc\u30c9\u304c\u30d6\u30e9\u30a6\u30b6\u3067\u3069\u306e\u3088\u3046\u306b\u5b9f\u884c\u3055\u308c\u308b\u304b\u3092\u6c7a\u5b9a\u3057\u307e\u3059\u3002<\/p>\n
\u3053\u306escript<\/code>\u8981\u7d20\u3092 HTML\u6587\u66f8\u306ebody\u5185\u306e\u3059\u3079\u3066\u306e\u8981\u7d20\u3088\u308a\u3082\u4e0a\u306b\u914d\u7f6e\u3059\u308b\u3068\u3001DOM\u304c\u8aad\u307f\u8fbc\u307e\u308c\u308b\u524d\u306bJavaScript\u306e\u30b3\u30fc\u30c9\u304c\u5b9f\u884c\u3055\u308c\u308b\u3053\u3068\u306b\u3002<\/p>\n
\u3064\u307e\u308a\u3001JavaScript\u304cDOM\u8981\u7d20\u306e\u8aad\u307f\u8fbc\u307f\u3092\u5f85\u305f\u305a\u306b\u5b9f\u884c\u3055\u308c\u308b\u305f\u3081\u3001DOM\u8981\u7d20\u3078\u306e\u53c2\u7167\u304c\u306a\u3044\u3053\u3068\u3092\u610f\u5473\u3057\u307e\u3059\u3002<\/p>\n
\u4f8b\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n
<!DOCTYPE html>\n<html>\n  <head>\n    <title>Error Tutorial<\/title>\n  <\/head>\n  <body>\n    <script src=\"app.js\"><\/script>\n    <h1 id=\"content\">Hello World!<\/h1>\n  <\/body>\n<\/html><\/code><\/pre>\n
\u4e0a\u306e\u30b3\u30fc\u30c9\u3067\u306f\u3001script<\/code>\u8981\u7d20\u304ch1<\/code>\u8981\u7d20\u306e\u4e0a\u306b\u914d\u7f6e\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n
\u4ee5\u4e0b\u306f\u3001h1<\/code>\u8981\u7d20\u306eID\u3092\u4f7f\u3063\u3066\u3001\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308bJavaScript\u306e\u30b3\u30fc\u30c9\u3067\u3059\u3002<\/p>\n
let content = document.getElementById(\"content\");\nconsole.log(content.textContent);\n\/\/ Uncaught TypeError: Cannot read properties of null (reading 'textContent');<\/code><\/pre>\n
\u3053\u306e\u3088\u3046\u306b\u3001h1<\/code>\u8981\u7d20\u3088\u308a\u524d\u306b\u3042\u308bJavaScript\u30b3\u30fc\u30c9\u304cDOM\u306b\u8ffd\u52a0\u3055\u308c\u305f\u305f\u3081\u3001\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u304c\u6295\u3052\u3089\u308c\u307e\u3057\u305f\u3002<\/p>\n
\u3053\u308c\u3092\u89e3\u6c7a\u3059\u308b\u306b\u306f\u3001body<\/code>\u30bf\u30b0\u3092\u9589\u3058\u308b\u524d\u306b\u3001script<\/code>\u8981\u7d20\u3092\u8a18\u8ff0\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u305d\u3046\u3059\u308b\u3053\u3068\u3067\u3001DOM\u306e\u3059\u3079\u3066\u306e\u8981\u7d20\u304c\u8aad\u307f\u8fbc\u307e\u308c\u305f\u5f8c\u3001\u30b9\u30af\u30ea\u30d7\u30c8\u304c\u5b9f\u884c\u3055\u308c\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
<!DOCTYPE html>\n<html>\n  <head>\n    <title>Error Tutorial<\/title>\n  <\/head>\n  <body>\n    <h1 id=\"content\">Hello World!<\/h1>\n    <script src=\"app.js\"><\/script>\n  <\/body>\n<\/html><\/code><\/pre>\n
\u307e\u3068\u3081<\/h2>\n
\u958b\u767a\u4f5c\u696d\u306b\u30a8\u30e9\u30fc\u306f\u3064\u304d\u3082\u306e\u3002\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u4e2d\u306b\u306f\u30a4\u30e9\u30a4\u30e9\u3059\u308b\u3053\u3068\u3082\u3042\u308a\u307e\u3059\u304c\u3001\u305d\u306e\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u8a00\u8a9e\u306b\u3064\u3044\u3066\u3001\u3088\u308a\u6df1\u304f\u5b66\u3073\u3001\u30b9\u30ad\u30eb\u3092\u78e8\u304f\u7ce7\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n
\u30a8\u30e9\u30fc\u306b\u906d\u9047\u3057\u305f\u3089\u3001\u5fc5\u305a\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u306b\u6ce8\u76ee\u3057\u307e\u3057\u3087\u3046\u3002\u4f55\u304b\u3089\u624b\u3092\u3064\u3051\u3066\u3001\u4f55\u3092\u4fee\u6b63\u3059\u308c\u3070\u3044\u3044\u306e\u304b\u3092\u7d10\u89e3\u304f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u307e\u305f\u3001\u540c\u3058\u3088\u3046\u306a\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u3092\u6301\u3064\u4ed6\u306e\u30a8\u30e9\u30fc\u3082\u89e3\u6c7a\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n
\u30a6\u30a7\u30d6\u30b5\u30a4\u30c8\u3092\u69cb\u7bc9\u3059\u308b\u306b\u306f\u3001\u3055\u307e\u3056\u307e\u306a\u30b9\u30ad\u30eb\u304c\u6c42\u3081\u3089\u308c\u307e\u3059\u3002\u8a00\u8a9e\u3084\u30c4\u30fc\u30eb\u3092\u52b9\u7387\u7684\u306b\u4f7f\u7528\u3067\u304d\u308b\u3088\u3046\u3001\u7df4\u7fd2\u3082\u91cd\u306d\u308b\u3053\u3068\u304c\u5fc5\u8981\u3067\u3059\u3002DevKinsta\u3092\u4f7f\u3046\u3068\u3001\u30c7\u30b6\u30a4\u30f3\u304b\u3089\u958b\u767a\u3001\u30c7\u30d7\u30ed\u30a4\u307e\u3067\u3001\u5168\u3066\u306e\u4f5c\u696d\u3092\u30ed\u30fc\u30ab\u30eb\u30de\u30b7\u30f3\u3067\u7c21\u5358\u306b\u884c\u3046\u3053\u3068\u304c\u3067\u304d\u30012\u4e075,000\u4eba\u4ee5\u4e0a\u306e\u958b\u767a\u8005\u3001\u30a6\u30a7\u30d6\u30c7\u30b6\u30a4\u30ca\u30fc\u3001\u30d5\u30ea\u30fc\u30e9\u30f3\u30b5\u30fc\u304c\u4f7f\u7528\u3057\u3066\u3044\u307e\u3059\u3002\u7121\u6599\u30c0\u30a6\u30f3\u30ed\u30fc\u30c9\u306f\u3053\u3061\u3089<\/a>\u304b\u3089\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u3069\u306e\u3088\u3046\u306a\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u8a00\u8a9e\u3067\u3042\u3063\u3066\u3082\u3001\u7fd2\u5f97\u4e2d\u3084\u4f7f\u7528 …<\/p>\n","protected":false},"author":240,"featured_media":40521,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_kinsta_gated_content":false,"_kinsta_gated_content_redirect":"","footnotes":""},"tags":[],"topic":[776],"class_list":["post-40520","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","topic-javascript-errors"],"yoast_head":"\nJavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5<\/title>\n<meta name=\"description\" content=\"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\" \/>\n<meta property=\"og:locale\" content=\"ja_JP\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5\" \/>\n<meta property=\"og:description\" content=\"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002\" \/>\n<meta property=\"og:url\" content=\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\" \/>\n<meta property=\"og:site_name\" content=\"Kinsta\u00ae\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/Kinsta-Japan-334616080691171\/\" \/>\n<meta property=\"article:published_time\" content=\"2023-01-02T12:27:07+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-01T19:47:36+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1460\" \/>\n\t<meta property=\"og:image:height\" content=\"730\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"author\" content=\"Ihechikara Abba\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:description\" content=\"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002\" \/>\n<meta name=\"twitter:image\" content=\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\" \/>\n<meta name=\"twitter:creator\" content=\"@Kinsta_JP\" \/>\n<meta name=\"twitter:site\" content=\"@Kinsta_JP\" \/>\n<meta name=\"twitter:label1\" content=\"\u57f7\u7b46\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"Ihechikara Abba\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u63a8\u5b9a\u8aad\u307f\u53d6\u308a\u6642\u9593\" \/>\n\t<meta name=\"twitter:data2\" content=\"2\u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\"},\"author\":{\"name\":\"Ihechikara Abba\",\"@id\":\"https:\/\/kinsta.com\/jp\/#\/schema\/person\/ac373ce22a016949523f7e464fdcae26\"},\"headline\":\"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5\",\"datePublished\":\"2023-01-02T12:27:07+00:00\",\"dateModified\":\"2025-10-01T19:47:36+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\"},\"wordCount\":130,\"commentCount\":1,\"publisher\":{\"@id\":\"https:\/\/kinsta.com\/jp\/#organization\"},\"image\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\",\"inLanguage\":\"ja\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\",\"url\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\",\"name\":\"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5\",\"isPartOf\":{\"@id\":\"https:\/\/kinsta.com\/jp\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\",\"datePublished\":\"2023-01-02T12:27:07+00:00\",\"dateModified\":\"2025-10-01T19:47:36+00:00\",\"description\":\"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002\",\"breadcrumb\":{\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#breadcrumb\"},\"inLanguage\":\"ja\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"ja\",\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage\",\"url\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\",\"contentUrl\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png\",\"width\":1460,\"height\":730},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/kinsta.com\/jp\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"JavaScript\u30a8\u30e9\u30fc\",\"item\":\"https:\/\/kinsta.com\/jp\/topics\/javascript-errors\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/kinsta.com\/jp\/#website\",\"url\":\"https:\/\/kinsta.com\/jp\/\",\"name\":\"Kinsta\u00ae\",\"description\":\"\u9ad8\u901f\u304b\u3064\u5805\u7262\u306a\u30d7\u30ec\u30df\u30a2\u30e0\u30b5\u30fc\u30d0\u30fc\u30b5\u30fc\u30d3\u30b9\",\"publisher\":{\"@id\":\"https:\/\/kinsta.com\/jp\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/kinsta.com\/jp\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"ja\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/kinsta.com\/jp\/#organization\",\"name\":\"Kinsta\",\"url\":\"https:\/\/kinsta.com\/jp\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"ja\",\"@id\":\"https:\/\/kinsta.com\/jp\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/12\/kinsta-logo.jpeg\",\"contentUrl\":\"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/12\/kinsta-logo.jpeg\",\"width\":500,\"height\":500,\"caption\":\"Kinsta\"},\"image\":{\"@id\":\"https:\/\/kinsta.com\/jp\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/www.facebook.com\/Kinsta-Japan-334616080691171\/\",\"https:\/\/x.com\/Kinsta_JP\",\"https:\/\/www.instagram.com\/kinstahosting\/\",\"https:\/\/www.linkedin.com\/company\/kinsta\/\",\"https:\/\/www.pinterest.com\/kinstahosting\/\",\"https:\/\/www.youtube.com\/c\/Kinsta\"]},{\"@type\":\"Person\",\"@id\":\"https:\/\/kinsta.com\/jp\/#\/schema\/person\/ac373ce22a016949523f7e464fdcae26\",\"name\":\"Ihechikara Abba\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"ja\",\"@id\":\"https:\/\/kinsta.com\/jp\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/483df106a6ba0c29683578302f74008c?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/483df106a6ba0c29683578302f74008c?s=96&d=mm&r=g\",\"caption\":\"Ihechikara Abba\"},\"description\":\"Ihechikara is a software developer and technical writer. He enjoys writing articles on web technologies, programming, and IT-related topics. Connect with Ihechikara on Twitter.\",\"url\":\"https:\/\/kinsta.com\/jp\/blog\/author\/ihechivinabba\/\"}]}<\/script>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5","description":"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/","og_locale":"ja_JP","og_type":"article","og_title":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5","og_description":"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002","og_url":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/","og_site_name":"Kinsta\u00ae","article_publisher":"https:\/\/www.facebook.com\/Kinsta-Japan-334616080691171\/","article_published_time":"2023-01-02T12:27:07+00:00","article_modified_time":"2025-10-01T19:47:36+00:00","og_image":[{"width":1460,"height":730,"url":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","type":"image\/png"}],"author":"Ihechikara Abba","twitter_card":"summary_large_image","twitter_description":"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002","twitter_image":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","twitter_creator":"@Kinsta_JP","twitter_site":"@Kinsta_JP","twitter_misc":{"\u57f7\u7b46\u8005":"Ihechikara Abba","\u63a8\u5b9a\u8aad\u307f\u53d6\u308a\u6642\u9593":"2\u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#article","isPartOf":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/"},"author":{"name":"Ihechikara Abba","@id":"https:\/\/kinsta.com\/jp\/#\/schema\/person\/ac373ce22a016949523f7e464fdcae26"},"headline":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5","datePublished":"2023-01-02T12:27:07+00:00","dateModified":"2025-10-01T19:47:36+00:00","mainEntityOfPage":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/"},"wordCount":130,"commentCount":1,"publisher":{"@id":"https:\/\/kinsta.com\/jp\/#organization"},"image":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage"},"thumbnailUrl":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","inLanguage":"ja","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/","url":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/","name":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5","isPartOf":{"@id":"https:\/\/kinsta.com\/jp\/#website"},"primaryImageOfPage":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage"},"image":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage"},"thumbnailUrl":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","datePublished":"2023-01-02T12:27:07+00:00","dateModified":"2025-10-01T19:47:36+00:00","description":"JavaScript\u3067\u300cUncaught TypeError\u300d\u3068\u3044\u3046\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u539f\u56e0\u306f\u3001\u3044\u304f\u3064\u304b\u3042\u308a\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u4e3b\u306a\u539f\u56e0\u3068\u305d\u306e\u5bfe\u51e6\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u3054\u8aac\u660e\u3057\u307e\u3059\u3002","breadcrumb":{"@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#breadcrumb"},"inLanguage":"ja","potentialAction":[{"@type":"ReadAction","target":["https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/"]}]},{"@type":"ImageObject","inLanguage":"ja","@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#primaryimage","url":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","contentUrl":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/01\/uncaught-typeerror-cannot-read-property.png","width":1460,"height":730},{"@type":"BreadcrumbList","@id":"https:\/\/kinsta.com\/jp\/blog\/uncaught-typeerror-cannot-read-property\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/kinsta.com\/jp\/"},{"@type":"ListItem","position":2,"name":"JavaScript\u30a8\u30e9\u30fc","item":"https:\/\/kinsta.com\/jp\/topics\/javascript-errors\/"},{"@type":"ListItem","position":3,"name":"JavaScript\u306e\u300cUncaught TypeError: Cannot read property\u300d\u30a8\u30e9\u30fc\u3092\u89e3\u6c7a\u3059\u308b\u65b9\u6cd5"}]},{"@type":"WebSite","@id":"https:\/\/kinsta.com\/jp\/#website","url":"https:\/\/kinsta.com\/jp\/","name":"Kinsta\u00ae","description":"\u9ad8\u901f\u304b\u3064\u5805\u7262\u306a\u30d7\u30ec\u30df\u30a2\u30e0\u30b5\u30fc\u30d0\u30fc\u30b5\u30fc\u30d3\u30b9","publisher":{"@id":"https:\/\/kinsta.com\/jp\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/kinsta.com\/jp\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"ja"},{"@type":"Organization","@id":"https:\/\/kinsta.com\/jp\/#organization","name":"Kinsta","url":"https:\/\/kinsta.com\/jp\/","logo":{"@type":"ImageObject","inLanguage":"ja","@id":"https:\/\/kinsta.com\/jp\/#\/schema\/logo\/image\/","url":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/12\/kinsta-logo.jpeg","contentUrl":"https:\/\/kinsta.com\/jp\/wp-content\/uploads\/sites\/6\/2023\/12\/kinsta-logo.jpeg","width":500,"height":500,"caption":"Kinsta"},"image":{"@id":"https:\/\/kinsta.com\/jp\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/Kinsta-Japan-334616080691171\/","https:\/\/x.com\/Kinsta_JP","https:\/\/www.instagram.com\/kinstahosting\/","https:\/\/www.linkedin.com\/company\/kinsta\/","https:\/\/www.pinterest.com\/kinstahosting\/","https:\/\/www.youtube.com\/c\/Kinsta"]},{"@type":"Person","@id":"https:\/\/kinsta.com\/jp\/#\/schema\/person\/ac373ce22a016949523f7e464fdcae26","name":"Ihechikara Abba","image":{"@type":"ImageObject","inLanguage":"ja","@id":"https:\/\/kinsta.com\/jp\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/483df106a6ba0c29683578302f74008c?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/483df106a6ba0c29683578302f74008c?s=96&d=mm&r=g","caption":"Ihechikara Abba"},"description":"Ihechikara is a software developer and technical writer. He enjoys writing articles on web technologies, programming, and IT-related topics. Connect with Ihechikara on Twitter.","url":"https:\/\/kinsta.com\/jp\/blog\/author\/ihechivinabba\/"}]}},"acf":[],"_links":{"self":[{"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/posts\/40520","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/users\/240"}],"replies":[{"embeddable":true,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/comments?post=40520"}],"version-history":[{"count":7,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/posts\/40520\/revisions"}],"predecessor-version":[{"id":47946,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/posts\/40520\/revisions\/47946"}],"alternate":[{"embeddable":true,"hreflang":"en","title":"English","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/en"},{"embeddable":true,"hreflang":"it","title":"Italian","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/it"},{"embeddable":true,"hreflang":"pt","title":"Portuguese","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/pt"},{"embeddable":true,"hreflang":"fr","title":"French","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/fr"},{"embeddable":true,"hreflang":"de","title":"German","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/de"},{"embeddable":true,"hreflang":"ja","title":"Japanese","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/jp"},{"embeddable":true,"hreflang":"nl","title":"Dutch","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/nl"},{"embeddable":true,"hreflang":"es","title":"Spanish","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/es"},{"embeddable":true,"hreflang":"sv","title":"Swedish","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/se"},{"embeddable":true,"hreflang":"da","title":"Danish","href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/translations\/dk"},{"href":"https:\/\/kinsta.com\/jp\/wp-json\/kinsta\/v1\/posts\/40520\/tree"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/media\/40521"}],"wp:attachment":[{"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/media?parent=40520"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/tags?post=40520"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/kinsta.com\/jp\/wp-json\/wp\/v2\/topic?post=40520"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}