{"id":6838,"date":"2025-01-20T19:00:00","date_gmt":"2025-01-20T10:00:00","guid":{"rendered":"https:\/\/techmania.jp\/blog\/?p=6838"},"modified":"2025-05-01T19:20:34","modified_gmt":"2025-05-01T10:20:34","slug":"javascript-getelementbyid","status":"publish","type":"post","link":"https:\/\/techmania.jp\/blog\/javascript-getelementbyid\/","title":{"rendered":"\u3010JavaScript\u5165\u9580\u3011getElementById\u306e\u4f7f\u3044\u65b9\u3092\u308f\u304b\u308a\u3084\u3059\u304f\u5fb9\u5e95\u89e3\u8aac"},"content":{"rendered":"

JavaScript\u3067HTML\u3092\u64cd\u4f5c\u3059\u308b\u65b9\u6cd5\u306e\u3046\u3061\u6700\u3082\u57fa\u672c\u7684\u306a\u3082\u306e\u306b\u300cgetElementById\u300d\u3068\u3044\u3046\u3001HTML\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u304c\u3042\u308a\u307e\u3059\u3002getElementById\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u53d6\u5f97\u3057\u305f\u8981\u7d20\u306e\u5185\u5bb9\u3084\u30b9\u30bf\u30a4\u30eb\u3092\u5909\u66f4\u3059\u308b\u306e\u304c\u5bb9\u6613\u306b\u306a\u308b\u306a\u3069\u3001\u5f79\u7acb\u3064\u5834\u9762\u306f\u591a\u3005\u3042\u308a\u307e\u3059\u3002\u672c\u8a18\u4e8b\u3067\u306f\u3001JavaScript\u5b66\u7fd2\u8005\u5411\u3051\u306b<\/span>getElementById\u306e\u4f7f\u3044\u65b9\u3092\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u3092\u7528\u3044\u3066\u89e3\u8aac\u3057<\/span><\/span>\u307e\u3059\u3002<\/span><\/span><\/p>\n\n\n

getElementById\u3068\u306f<\/h2>\n\n\n

getElementById\u3068\u306f\u3001HTML\u5185\u306e\u30bf\u30b0\u306bid\u5c5e\u6027\u3067\u6307\u5b9a\u3057\u305f\u5024\u3092\u6301\u3064HTML\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002\u4efb\u610f\u306e\u8981\u7d20\u3092\u62bd\u51fa\u3057\u3066\u3001HTML\u3092\u66f8\u304d\u63db\u3048\u305f\u308a\u30b9\u30bf\u30a4\u30eb\u3092\u5909\u66f4\u3059\u308b\u3068\u3044\u3063\u305f\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002\u8981\u7d20\u306eid\u5c5e\u6027\u306f\u5e38\u306b”\u4e00\u610f\u3067\u3042\u308b”\uff08\u8907\u6570\u8aad\u307f\u53d6\u308c\u308b\u72b6\u614b\u306b\u306a\u3089\u306a\u3044\uff09\u3053\u3068\u304c\u6c42\u3081\u3089\u308c\u308b\u306e\u3067\u3001\u7279\u5b9a\u306e\u8981\u7d20\u306b\u7d20\u65e9\u304f\u30a2\u30af\u30bb\u30b9\u3059\u308b\u5834\u5408\u306b\u6709\u52b9\u3067\u3059\u3002<\/p>\n

ID\u306b\u95a2\u3059\u308b\u30eb\u30fc\u30eb<\/strong><\/p>\n

ID\u306fHTML\u8981\u7d20\u306b\u4ed8\u3051\u3089\u308c\u305f\u8b58\u5225\u5b50\uff08identifier\uff09\u306e\u3053\u3068\u3067\u3042\u308a\u3001\u540c\u4e00HTML\u5185\u3067\u91cd\u8907\u3057\u3066\u306f\u306a\u3089\u305a\u3001\u4e00\u610f\u306a\u5024\u3067\u3042\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002\u307e\u305f\u3001getElementById\u30e1\u30bd\u30c3\u30c9\u3067\u53d6\u5f97\u3067\u304d\u308b\u8981\u7d20\u306f\u4e00\u3064\u3067\u3042\u308b\u305f\u3081\u3001\u8907\u6570\u306e\u8981\u7d20\u304c\u540c\u3058ID\u3092\u6301\u3064\u5834\u5408\uff08\u540c\u4e00HTML\u5185\u3067\u91cd\u8907ID\u304c\u5b58\u5728\u3059\u308b\uff09\u306f\u3001\u6700\u521d\u306b\u4e00\u81f4\u3057\u305f\u8981\u7d20\u3060\u3051\u3092\u8fd4\u3057\u307e\u3059\u3002\u307e\u305f\u3001\u6307\u5b9a\u3057\u305fID\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306fNULL\u5024\u3092\u8fd4\u3057\u307e\u3059\u3002<\/span><\/span><\/p>\n

id\u5c5e\u6027\u3092\u6301\u305f\u306a\u3044\u8981\u7d20\u306b\u30a2\u30af\u30bb\u30b9\u3059\u308b\u5834\u5408\u306f\u3001querySelector()\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3046\u3053\u3068\u3067\u4efb\u610f\u306e\u30bb\u30ec\u30af\u30bf\u3067\u8981\u7d20\u3092\u691c\u7d22\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n

\u3042\u306a\u305f\u306e\u3054\u5e0c\u671b\u306b\u6cbf\u3063\u305f\u6848\u4ef6\u304c\u5fc5\u305a<\/span>\u898b\u3064\u304b\u308a\u307e\u3059
\u3010\u30d5\u30ea\u30fc\u30e9\u30f3\u30b9\u5411\u3051\u3011\u9ad8\u53ce\u5165<\/span>\u30fb<\/span>\u597d\u5f85\u9047<\/span>\u306e\u6848\u4ef6\u3092\u3054\u7d39\u4ecb<\/span>\r\n<\/p><\/a>\r\n<\/div>\r\n\r\n

\"TECH<\/a>\r\n<\/div>\r\n\r\n
\r\n

\u226b\u307e\u305a\u306f\u7c21\u535860<\/span>\u79d2\u3067\u7121\u6599\u304a\u554f\u3044\u5408\u308f\u305b<\/span>\u304b\u3089\u226a\r\n<\/p><\/a>\r\n<\/div>\n\n\n

\u3010\u4f7f\u7528\u30a4\u30e1\u30fc\u30b8\u3011<\/strong><\/p>\n\n\n

document.getElementById(id)<\/code><\/pre><\/div>\n\n\n
\u300cgetElementById\u300d\u3092\u300cgetElementByID\u300d\u3068\u3057\u3066\u3057\u307e\u3046\u3068\u3001\u30e1\u30bd\u30c3\u30c9\u3068\u3057\u3066\u6a5f\u80fd\u3057\u306a\u3044\u306e\u3067\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n
\u3010\u5f15\u6570\u3011<\/strong><\/p>\n
\u5f15\u6570\u306b\u306f\u53d6\u5f97\u3057\u305f\u3044\u8981\u7d20\u306eID\u5024\u3092\u8a18\u8ff0\u3057\u307e\u3059\u3002\u306a\u304a\u3001ID\u5024\u306e\u6587\u5b57\u5217\u306f\u5927\u6587\u5b57\u3068\u5c0f\u6587\u5b57\u3068\u3067\u533a\u5225\u3055\u308c\u307e\u3059\u3002<\/p>\n
\uff08\u4f8b\uff09’example’<\/span><\/p>\n
\u3010\u623b\u308a\u5024\u3011<\/strong><\/span><\/p>\n
ID\u5024\uff08id\u5c5e\u6027\u3067\u6307\u5b9a\u3055\u308c\u305f\u6587\u5b57\u5217\uff09\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u3092\u8fd4\u3057\u307e\u3059\u3002HTML\u5185\u306b\u4e00\u81f4\u3059\u308b\u8981\u7d20\u304c\u306a\u3044\u5834\u5408\u306fNULL\u5024\u3092\u8fd4\u3057\u307e\u3059\u3002<\/span><\/span><\/p>\n\n\n
getElementById\u306e\u4f7f\u3044\u65b9<\/h2>\n\n\n\n
\u3010\u4f8b1\u3011\u8981\u7d20\u3092\u53d6\u5f97\u3059\u308b<\/h3>\n\n\n
\u6bb5\u843d\u30bf\u30b0\u3092ID\u3067\u8981\u7d20\u3092\u53d6\u5f97\u3057\u3001JavaScript\u30b3\u30f3\u30bd\u30fc\u30eb\u306b\u8868\u793a\u3055\u305b\u307e\u3059\u3002<\/p>\n
\u3010\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
<html>\n<body>\n    <p id="sample">\u3053\u3093\u306b\u3061\u306f<\/p>\n    <script>\n        console.log(document.getElementById("sample"));\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre><\/div>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n
\n
<p id=”sample”>\u3053\u3093\u306b\u3061\u306f<\/p><\/strong><\/p>\n<\/div>\n
\u30d6\u30e9\u30a6\u30b6\u3067HTML\u30d5\u30a1\u30a4\u30eb\u3092\u958b\u304d\u3001\u691c\u8a3c\u30e2\u30fc\u30c9\u3092\u7acb\u3061\u4e0a\u3052\u3066\u300c\u30b3\u30f3\u30bd\u30fc\u30eb\u300d\u306e\u30bf\u30d6\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3068\u4e0a\u306e\u3088\u3046\u306bHTML\u8981\u7d20\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n
\u3061\u306a\u307f\u306b\u3001JavaScript\u3067\u5909\u6570\u306b\u4ee3\u5165\u3059\u308b\u5834\u5408\u306f\u6b21\u306e\u3088\u3046\u306b\u8a18\u8ff0\u3057\u307e\u3059\u3002<\/p>\n\n\n
\u3010\u57fa\u672c\u69cb\u6587\u3011<\/strong><\/p>\n\n\n\n
\/\/ \u3042\u3068\u304b\u3089\u5909\u6570\u306b\u5225\u306e\u5024\u3092\u4ee3\u5165\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308b\u5834\u5408\nlet \u5909\u6570\u540d = document.getElementById(id\u5024);\n\n\/\/ \u5024\u3092\u5909\u66f4\u3057\u306a\u3044\u3053\u3068\u304c\u6700\u521d\u304b\u3089\u5206\u304b\u3063\u3066\u3044\u308b\u5834\u5408\nconst \u5909\u6570\u540d = document.getElementById(id\u5024);<\/code><\/pre><\/div>\n\n\n\n
\u3010\u4f8b2\u3011\u8981\u7d20\u306e\u30c6\u30ad\u30b9\u30c8\u90e8\u5206\u3092\u53d6\u5f97\u3059\u308b<\/h3>\n\n\n
\u6bb5\u843d\u30bf\u30b0\u3092ID\u3067\u8981\u7d20\u3092\u53d6\u5f97\u3057\u3001textContent\u30d7\u30ed\u30d1\u30c6\u30a3\u3067\u8981\u7d20\u306e\u4e2d\u8eab\u3067\u3042\u308b\u30c6\u30ad\u30b9\u30c8\u90e8\u5206\u3092JavaScript\u30b3\u30f3\u30bd\u30fc\u30eb\u306b\u8868\u793a\u3055\u305b\u307e\u3059\u3002<\/p>\n
\u3010\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
<html>\n <body>\n  <p id="sample">\u3053\u3093\u306b\u3061\u306f<\/p>\n  <script>\n  console.log(document.getElementById("sample").textContent);\n  <\/script>\n <\/body>\n<\/html><\/code><\/pre><\/div>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n
\n
\u3053\u3093\u306b\u3061\u306f<\/strong><\/p>\n<\/div>\n\n\n
\u3010\u4f8b3\u3011\u5909\u6570\u3067ID\u3092\u6307\u5b9a\u3059\u308b<\/h3>\n\n\n
\u5f15\u6570\u3092\u6587\u5b57\u5217\u3067\u306f\u306a\u304f\u3001\u5909\u6570\u3067\u6307\u5b9a\u3057\u307e\u3059\u3002<\/span><\/p>\n
\u3010\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
<html>\n<body>\n    <p id="sample">\u3053\u3093\u306b\u3061\u306f<\/p>\n    <script>\n        let id = "sample";\n        console.log(document.getElementById(id));\n    <\/script>\n<\/body>\n<\/html><\/code><\/pre><\/div>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n
\n
<p id=”sample”>\u3053\u3093\u306b\u3061\u306f<\/p><\/strong><\/p>\n<\/div>\n
\u5909\u6570\u300cid\u300d\u306b\u6bb5\u843d\u30bf\u30b0\u306eID\u540d\u300csample\u300d\u304c\u683c\u7d0d\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u305d\u306e\u305f\u3081\u3001\u5909\u6570\u3092getElementById\u306e\u5f15\u6570\u306b\u6307\u5b9a\u3059\u308b\u3053\u3068\u3067\u6bb5\u843d\u30bf\u30b0\u8981\u7d20\u304c\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/span><\/p>\n\n\n
\u3010\u4f8b4\u3011\u8981\u7d20\u306e\u4e2d\u8eab\u3092\u5909\u66f4\u3059\u308b<\/h3>\n\n\n
innerHTML\u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u8981\u7d20\u306e\u4e2d\u8eab\u3092\u5909\u66f4\u3067\u304d\u307e\u3059\u3002<\/span><\/p>\n
\u3010\u5b9f\u884c\u30b3\u30fc\u30c9\u3011<\/strong><\/p>\n\n\n
<html>\n<body>\n    <p id="sample">\u3053\u3093\u306b\u3061\u306f<\/p>\n    <input type="button" value="\u30af\u30ea\u30c3\u30af" onclick="fnc()">\n    <script>\n        const smp = document.getElementById("sample");\n        function fnc() {\n            smp.innerHTML = "\u3053\u3093\u3070\u3093\u306f";\n        }\n    <\/script>\n<\/body>\n<html><\/code><\/pre><\/div>\n\n\n
\u3010\u5b9f\u884c\u7d50\u679c\u3011<\/strong><\/p>\n
\u30dc\u30bf\u30f3\u3092\u30af\u30ea\u30c3\u30af\u3059\u308b\u3068\u6bb5\u843d\u30bf\u30b0\u5185\u306e\u6587\u5b57\u5217\u304c\u5909\u66f4\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n