{"id":275711,"date":"2024-05-16T14:34:17","date_gmt":"2024-05-16T06:34:17","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/275711.html"},"modified":"2024-05-16T14:34:23","modified_gmt":"2024-05-16T06:34:23","slug":"jacascript-%e9%a1%b9%e7%9b%ae%e6%80%8e%e4%b9%88%e5%af%b9-dom-%e8%8a%82%e7%82%b9%e8%bf%9b%e8%a1%8c%e8%8e%b7%e5%8f%96","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/275711.html","title":{"rendered":"jacascript \u9879\u76ee\u600e\u4e48\u5bf9 DOM \u8282\u70b9\u8fdb\u884c\u83b7\u53d6"},"content":{"rendered":"

\"jacascript<\/p>\n

\u5728JavaScript\u9879\u76ee\u4e2d\uff0c\u5bf9DOM\u8282\u70b9\u8fdb\u884c\u83b7\u53d6\u7684\u6838\u5fc3\u65b9\u6cd5\u5305\u62ecgetElementById<\/strong>\u3001getElementsByClassName<\/strong>\u3001getElementsByTagName<\/strong>\u3001querySelector<\/strong> \u548c querySelectorAll<\/strong>\u3002\u8fd9\u4e9b\u65b9\u6cd5\u53ef\u4ee5\u8ba9\u5f00\u53d1\u8005\u6839\u636e\u4e0d\u540c\u9700\u6c42\u9009\u62e9\u6027\u5730\u83b7\u53d6DOM\u5143\u7d20\u3002\u4ee5 querySelector<\/strong> \u548c querySelectorAll<\/strong> \u4e3a\u4f8b\uff0c\u5b83\u4eec\u63d0\u4f9b\u4e86\u6700\u5f3a\u5927\u548c\u7075\u6d3b\u7684\u65b9\u5f0f\u6765\u5b9a\u4f4dDOM\u8282\u70b9\uff0c\u56e0\u4e3a\u5b83\u4eec\u5141\u8bb8\u5f00\u53d1\u8005\u4f7f\u7528CSS\u9009\u62e9\u5668\u8bed\u6cd5\u53bb\u67e5\u8be2DOM\u3002\u6b64\u5916\uff0cquerySelector<\/strong> \u8fd4\u56de\u6587\u6863\u4e2d\u4e0e\u6307\u5b9a\u9009\u62e9\u5668\u6216\u9009\u62e9\u5668\u7ec4\u5339\u914d\u7684\u7b2c\u4e00\u4e2aElement\u5bf9\u8c61\uff0c\u82e5\u6ca1\u6709\u627e\u5230\u5339\u914d\u9879\u5219\u8fd4\u56denull\u3002\u800c querySelectorAll<\/strong> \u5219\u8fd4\u56de\u4e00\u4e2aNodeList\u5bf9\u8c61\uff0c\u5305\u542b\u6587\u6863\u4e2d\u6240\u6709\u4e0e\u6307\u5b9a\u9009\u62e9\u5668\u6216\u9009\u62e9\u5668\u7ec4\u5339\u914d\u7684\u5143\u7d20\uff0c\u5982\u679c\u6ca1\u6709\u5339\u914d\u9879\u5219\u8fd4\u56de\u4e00\u4e2a\u7a7a\u7684NodeList\u3002<\/p>\n<\/p>\n

\u4e00\u3001GETELEMENTBYID<\/h3>\n<\/p>\n

getElementById<\/strong> \u65b9\u6cd5\u662f\u6700\u7b80\u5355\u76f4\u63a5\u7684\u83b7\u53d6\u5355\u4e2aDOM\u8282\u70b9\u7684\u65b9\u6cd5\u3002\u6b64\u65b9\u6cd5\u63a5\u53d7\u4e00\u4e2a\u5b57\u7b26\u4e32\u53c2\u6570\uff0c\u8be5\u5b57\u7b26\u4e32\u6307\u5b9a\u4e86\u8981\u83b7\u53d6\u7684\u5143\u7d20\u7684\u552f\u4e00id\u3002\u5f53\u6587\u6863\u4e2d\u5b58\u5728\u591a\u4e2a\u76f8\u540cid\u7684\u5143\u7d20\u65f6\uff0cgetElementById<\/strong> \u53ea\u4f1a\u8fd4\u56de\u7b2c\u4e00\u4e2a\u5339\u914d\u7684\u5143\u7d20\u3002<\/p>\n<\/p>\n

    \n
  • \u4f7f\u7528\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n

    var element = document.getElementById('myElement');<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u8fd9\u884c\u4ee3\u7801\u4f1a\u5728DOM\u4e2d\u5bfb\u627eid\u4e3a'myElement'\u7684\u5143\u7d20\uff0c\u5e76\u5c06\u5176\u5b58\u50a8\u5728\u53d8\u91cfelement\u4e2d\u3002\u5982\u679c\u627e\u4e0d\u5230\u8be5\u5143\u7d20\uff0c\u53d8\u91cfelement\u7684\u503c\u5c06\u662fnull\u3002<\/p>\n<\/p>\n
      \n
    • \u6ce8\u610f\u4e8b\u9879\uff1a<\/li>\n<\/ul>\n
      \u53ea\u6709\u5177\u6709id\u5c5e\u6027\u7684\u5143\u7d20\u624d\u80fd\u88abgetElementById\u627e\u5230\uff0c\u4e14\u9700\u8981\u6ce8\u610fid\u5c5e\u6027\u5728\u4e00\u4e2aHTML\u6587\u6863\u4e2d\u5e94\u8be5\u662f\u552f\u4e00\u7684\u3002<\/p>\n<\/p>\n
      \u4e8c\u3001GETELEMENTSBYCLASSNAME<\/h3>\n<\/p>\n
      getElementsByClassName<\/strong> \u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2aHTMLCollection\u5bf9\u8c61\uff0c\u5305\u542b\u6587\u6863\u4e2d\u6240\u6709\u5177\u6709\u6307\u5b9a\u7c7b\u540d\u7684\u5143\u7d20\u3002\u4e0egetElementById\u4e0d\u540c\uff0c\u6b64\u65b9\u6cd5\u53ef\u4ee5\u8fd4\u56de\u591a\u4e2a\u5143\u7d20\u3002<\/p>\n<\/p>\n
        \n
      • \u4f7f\u7528\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n
        var elements = document.getElementsByClassName('myClass');<\/p>\n
        <\/code><\/pre>\n<\/p>\n
        \u8fd9\u6bb5\u4ee3\u7801\u5c06\u4f1a\u9009\u53d6\u6240\u6709\u542b\u6709\u7c7b\u540d'myClass'\u7684\u5143\u7d20\uff0c\u5e76\u5c06\u5b83\u4eec\u4f5c\u4e3a\u4e00\u4e2aHTMLCollection\u8fd4\u56de\u3002\u6b64\u65b9\u6cd5\u6839\u636e\u7c7b\u540d\u8fdb\u884c\u5339\u914d\uff0c\u56e0\u6b64\u53ef\u4ee5\u8fd4\u56de\u96f6\u4e2a\u3001\u4e00\u4e2a\u6216\u591a\u4e2a\u5339\u914d\u5143\u7d20\u3002<\/p>\n<\/p>\n
          \n
        • \u6ce8\u610f\u4e8b\u9879\uff1a<\/li>\n<\/ul>\n
          \u4f7f\u7528\u65f6\u5e94\u6ce8\u610f\u786e\u4fdd\u67e5\u8be2\u7684\u7c7b\u540d\u6b63\u786e\u65e0\u8bef\uff0c\u5e76\u4e14\u8be5\u65b9\u6cd5\u8fd4\u56de\u7684\u662f\u4e00\u4e2aHTMLCollection\u5bf9\u8c61\uff0c\u8be5\u5bf9\u8c61\u662f\u52a8\u6001\u7684\uff0c\u5f53\u6587\u6863\u4e2d\u7684\u5143\u7d20\u6539\u53d8\u65f6\uff0c\u96c6\u5408\u4e5f\u4f1a\u76f8\u5e94\u66f4\u65b0\u3002<\/p>\n<\/p>\n
          \u4e09\u3001GETELEMENTSBYTAGNAME<\/h3>\n<\/p>\n
          getElementsByTagName<\/strong> \u65b9\u6cd5\u7528\u4e8e\u83b7\u53d6\u5e26\u6709\u6307\u5b9a\u6807\u7b7e\u540d\u7684\u6240\u6709\u5143\u7d20\uff0c\u8fd4\u56de\u503c\u4e3a\u4e00\u4e2aHTMLCollection\u3002<\/p>\n<\/p>\n
            \n
          • \u4f7f\u7528\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n
            var elements = document.getElementsByTagName('p');<\/p>\n
            <\/code><\/pre>\n<\/p>\n
            \u8fd9\u884c\u4ee3\u7801\u8fd4\u56de\u9875\u9762\u4e2d\u6240\u6709<p><\/code>\u5143\u7d20\u7684\u96c6\u5408\u3002\u5982\u679c\u6ca1\u6709\u76f8\u5e94\u7684\u5143\u7d20\uff0c\u5219\u8fd4\u56de\u4e00\u4e2a\u7a7a\u7684HTMLCollection\u3002<\/p>\n<\/p>\n
              \n
            • \u6ce8\u610f\u4e8b\u9879\uff1a<\/li>\n<\/ul>\n
              getElementsByTagName\u8fd4\u56de\u7684\u52a8\u6001HTMLCollection\u4f1a\u968f\u7740\u6587\u6863\u7ed3\u6784\u7684\u5b9e\u65f6\u53d8\u5316\u800c\u66f4\u65b0\uff0c\u4e14\u5b83\u53ef\u4ee5\u4f5c\u7528\u4e8e\u4efb\u610f\u5143\u7d20\uff0c\u800c\u4e0d\u4ec5\u4ec5\u662fdocument\u3002<\/p>\n<\/p>\n
              \u56db\u3001QUERYSELECTOR<\/h3>\n<\/p>\n
              querySelector<\/strong> \u662f\u4e00\u4e2a\u5f3a\u5927\u7684DOM\u67e5\u8be2\u65b9\u6cd5\uff0c\u5b83\u5141\u8bb8\u5f00\u53d1\u8005\u4f7f\u7528CSS\u9009\u62e9\u5668\u8bed\u6cd5\u5b9a\u4f4d\u5355\u4e2a\u5143\u7d20\u3002<\/p>\n<\/p>\n
                \n
              • \u4f7f\u7528\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n
                var element = document.querySelector('.myClass');<\/p>\n
                <\/code><\/pre>\n<\/p>\n
                \u8fd9\u6bb5\u4ee3\u7801\u67e5\u627e\u7b2c\u4e00\u4e2aclass\u4e3a'myClass'\u7684\u5143\u7d20\u3002\u5982\u679c\u6ca1\u6709\u627e\u5230\u4efb\u4f55\u5339\u914d\u5143\u7d20\uff0c\u8fd4\u56de\u503c\u5c06\u662fnull\u3002<\/p>\n<\/p>\n
                  \n
                • \u6ce8\u610f\u4e8b\u9879\uff1a<\/li>\n<\/ul>\n
                  querySelector\u5bf9\u6027\u80fd\u6709\u4e00\u5b9a\u5f71\u54cd\uff0c\u7279\u522b\u662f\u5f53\u5bf9\u5927\u578b\u6587\u6863\u6216\u5728\u9875\u9762\u5143\u7d20\u8f83\u591a\u65f6\u8fdb\u884c\u590d\u6742\u9009\u62e9\u5668\u7684\u67e5\u8be2\u3002\u56e0\u6b64\uff0c\u5e94\u5f53\u5728\u786e\u4fdd\u5fc5\u8981\u65f6\u624d\u4f7f\u7528\u5b83\u3002<\/p>\n<\/p>\n
                  \u4e94\u3001QUERYSELECTORALL<\/h3>\n<\/p>\n
                  querySelectorAll<\/strong> \u65b9\u6cd5\u8fd4\u56de\u7684\u662f\u4e00\u4e2aNodeList\u5bf9\u8c61\uff0c\u5176\u4e2d\u5305\u542b\u6240\u6709\u5339\u914d\u6307\u5b9aCSS\u9009\u62e9\u5668\u7684\u5143\u7d20\u3002<\/p>\n<\/p>\n
                    \n
                  • \u4f7f\u7528\u793a\u4f8b\uff1a<\/li>\n<\/ul>\n
                    var elements = document.querySelectorAll('div.myClass');<\/p>\n
                    <\/code><\/pre>\n<\/p>\n
                    \u8fd9\u884c\u4ee3\u7801\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u6240\u6709<div><\/code>\u5143\u7d20\uff0c\u4e14class\u5305\u542b'myClass'\u7684NodeList\u5bf9\u8c61\u3002<\/p>\n<\/p>\n
                      \n
                    • \u6ce8\u610f\u4e8b\u9879\uff1a<\/li>\n<\/ul>\n
                      \u4e0equerySelector\u4e00\u6837\uff0cquerySelectorAll\u5bf9\u6027\u80fd\u6709\u4e00\u5b9a\u5f71\u54cd\uff0c\u5e76\u4e14\u8fd4\u56de\u7684NodeList\u4e0d\u662f\u5b9e\u65f6\u52a8\u6001\u7684\uff0c\u5bf9\u6587\u6863\u7684\u540e\u7eed\u4fee\u6539\u4e0d\u4f1a\u53cd\u6620\u5230\u5df2\u7ecf\u8fd4\u56de\u7684NodeList\u4e2d\u3002<\/p>\n<\/p>\n
                      \u5728\u5b9e\u9645\u9879\u76ee\u4e2d\uff0c\u5408\u7406\u9009\u62e9\u4e0a\u8ff0\u65b9\u6cd5\u80fd\u591f\u5e2e\u52a9\u5f00\u53d1\u8005\u9ad8\u6548\u5730\u5bf9DOM\u6811\u8fdb\u884c\u67e5\u8be2\u548c\u64cd\u63a7\uff0c\u662fJavaScript DOM\u7f16\u7a0b\u7684\u57fa\u7840\u3002<\/p>\n<\/p>\n
                      \u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
                      1. DOM \u8282\u70b9\u662f\u4ec0\u4e48\uff0c\u4ee5\u53ca\u5982\u4f55\u5728 JavaScript \u9879\u76ee\u4e2d\u83b7\u53d6\u5b83\u4eec\uff1f<\/strong><\/p>\n
                      DOM\uff08\u6587\u6863\u5bf9\u8c61\u6a21\u578b\uff09\u8282\u70b9\u662f HTML \u6216 XML \u6587\u6863\u4e2d\u7684\u5143\u7d20\u3002\u5b83\u4eec\u53ef\u4ee5\u662f\u6807\u7b7e\u3001\u6587\u672c\u3001\u5c5e\u6027\u6216\u6ce8\u91ca\u7b49\u3002\u8981\u5728 JavaScript \u9879\u76ee\u4e2d\u83b7\u53d6 DOM \u8282\u70b9\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u51e0\u79cd\u65b9\u6cd5\uff1a<\/p>\n
                        \n
                      • \u4f7f\u7528 document \u5bf9\u8c61\u7684 getElementById() \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u6839\u636e\u6307\u5b9a\u7684 id \u83b7\u53d6 DOM \u8282\u70b9\u3002<\/li>\n
                      • \u4f7f\u7528 document \u5bf9\u8c61\u7684 getElementsByTagName() \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u6839\u636e\u6307\u5b9a\u7684\u6807\u7b7e\u540d\u79f0\u83b7\u53d6\u4e00\u4e2a DOM \u8282\u70b9\u7684\u96c6\u5408\u3002<\/li>\n
                      • \u4f7f\u7528 document \u5bf9\u8c61\u7684 getElementsByClassName() \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u6839\u636e\u6307\u5b9a\u7684\u7c7b\u540d\u83b7\u53d6\u4e00\u4e2a DOM \u8282\u70b9\u7684\u96c6\u5408\u3002<\/li>\n
                      • \u4f7f\u7528 document \u5bf9\u8c61\u7684 querySelector() \u6216 querySelectorAll() \u65b9\u6cd5\uff0c\u8fd9\u4e9b\u65b9\u6cd5\u4f7f\u7528 CSS \u9009\u62e9\u5668\u6765\u83b7\u53d6 DOM \u8282\u70b9\u3002<\/li>\n<\/ul>\n
                        2. \u5728 JavaScript \u9879\u76ee\u4e2d\uff0c\u5982\u4f55\u901a\u8fc7 DOM \u8282\u70b9\u4fee\u6539\u5143\u7d20\u7684\u6837\u5f0f\u548c\u5185\u5bb9\uff1f<\/strong><\/p>\n
                        \u8981\u901a\u8fc7 DOM \u8282\u70b9\u4fee\u6539\u5143\u7d20\u7684\u6837\u5f0f\uff0c\u53ef\u4ee5\u4f7f\u7528\u8282\u70b9\u7684 style \u5c5e\u6027\u3002\u901a\u8fc7\u8bbe\u7f6e\u8be5\u5c5e\u6027\u7684\u5404\u79cdCSS\u5c5e\u6027\u7684\u503c\uff0c\u53ef\u4ee5\u66f4\u6539\u5143\u7d20\u7684\u5916\u89c2\uff0c\u4f8b\u5982\u989c\u8272\u3001\u80cc\u666f\u3001\u8fb9\u6846\u7b49\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u4e00\u4e2a\u5143\u7d20\u7684\u80cc\u666f\u989c\u8272\u66f4\u6539\u4e3a\u7ea2\u8272\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n
                        var element = document.getElementById("myElement");\nelement.style.backgroundColor = "red";\n<\/code><\/pre>\n
                        \u8981\u901a\u8fc7 DOM \u8282\u70b9\u4fee\u6539\u5143\u7d20\u7684\u5185\u5bb9\uff0c\u53ef\u4ee5\u4f7f\u7528\u8282\u70b9\u7684 innerHTML \u5c5e\u6027\u3002\u8be5\u5c5e\u6027\u5141\u8bb8\u4f60\u8bbe\u7f6e\u5143\u7d20\u7684 HTML \u5185\u5bb9\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u4e00\u4e2a\u5143\u7d20\u7684\u6587\u672c\u66f4\u6539\u4e3a "Hello, World!"\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n
                        var element = document.getElementById("myElement");\nelement.innerHTML = "Hello, World!";\n<\/code><\/pre>\n
                        3. \u5982\u4f55\u5728 JavaScript \u9879\u76ee\u4e2d\u52a8\u6001\u521b\u5efa\u548c\u6dfb\u52a0 DOM \u8282\u70b9\uff1f<\/strong><\/p>\n
                        \u8981\u5728 JavaScript \u9879\u76ee\u4e2d\u52a8\u6001\u521b\u5efa\u548c\u6dfb\u52a0 DOM \u8282\u70b9\uff0c\u53ef\u4ee5\u4f7f\u7528 document \u5bf9\u8c61\u7684 createElement() \u548c appendChild() \u65b9\u6cd5\u3002createElement() \u65b9\u6cd5\u7528\u4e8e\u521b\u5efa\u65b0\u7684 DOM \u8282\u70b9\u5bf9\u8c61\uff0c\u800cappendChild() \u65b9\u6cd5\u7528\u4e8e\u5c06\u65b0\u521b\u5efa\u7684\u8282\u70b9\u6dfb\u52a0\u5230\u6307\u5b9a\u7684\u7236\u8282\u70b9\u4e2d\u3002<\/p>\n
                        \u4f8b\u5982\uff0c\u8981\u5728\u4e00\u4e2a div \u5143\u7d20\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u65b0\u7684 p \u5143\u7d20\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n
                        var parentElement = document.getElementById("myDiv");\nvar newElement = document.createElement("p");\nnewElement.innerHTML = "This is a new paragraph.";\nparentElement.appendChild(newElement);\n<\/code><\/pre>\n
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