{"id":168900,"date":"2024-05-08T16:33:47","date_gmt":"2024-05-08T08:33:47","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/168900.html"},"modified":"2024-05-08T16:33:51","modified_gmt":"2024-05-08T08:33:51","slug":"javascript-%e9%a1%b9%e7%9b%ae%e4%bb%a3%e7%a0%81%e5%a6%82%e4%bd%95%e8%8e%b7%e5%8f%96%e5%85%83%e7%b4%a0%e5%92%8c%e8%8a%82%e7%82%b9","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/168900.html","title":{"rendered":"JavaScript \u9879\u76ee\u4ee3\u7801\u5982\u4f55\u83b7\u53d6\u5143\u7d20\u548c\u8282\u70b9"},"content":{"rendered":"

\"JavaScript<\/p>\n

\u83b7\u53d6\u5143\u7d20\u548c\u8282\u70b9\u662fJavaScript\u5f00\u53d1\u4e2d\u7684\u57fa\u7840\u64cd\u4f5c\uff0c\u53ef\u4ee5\u901a\u8fc7\u591a\u79cdDOM\uff08Document Object Model\uff09\u65b9\u6cd5\u5b9e\u73b0\u3002\u5e38\u7528\u65b9\u6cd5\u5305\u62ec\uff1agetElementById()\u3001querySelector()\u3001getElementsByTagName()\u3001getElementsByClassName()<\/strong>\uff0c\u6bcf\u79cd\u65b9\u6cd5\u9488\u5bf9\u4e0d\u540c\u7684\u9700\u6c42\u63d0\u4f9b\u4e86\u89e3\u51b3\u65b9\u6848\u3002\u6bd4\u5982\uff0cgetElementById()<\/strong> \u65b9\u6cd5\u975e\u5e38\u9ad8\u6548\uff0c\u5b83\u901a\u8fc7\u5143\u7d20\u7684ID\u76f4\u63a5\u8bbf\u95ee\u7279\u5b9a\u5143\u7d20\u3002<\/p>\n<\/p>\n

\n

\u4e00\u3001\u901a\u8fc7 ID \u83b7\u53d6\u5143\u7d20<\/h3>\n<\/p>\n

getElementById()<\/strong> \u65b9\u6cd5\u662f\u6700\u5e38\u89c1\u7684\u8bbf\u95ee\u5143\u7d20\u7684\u65b9\u5f0f\u3002\u6bcf\u4e2aHTML\u5143\u7d20\u53ef\u4ee5\u6709\u4e00\u4e2aID\u5c5e\u6027\uff0c\u8fd9\u4e2a\u5c5e\u6027\u5728\u6587\u6863\u4e2d\u662f\u552f\u4e00\u7684\u3002\u56e0\u6b64\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u63d0\u4f9b\u4e86\u4e00\u79cd\u5feb\u901f\u3001\u51c6\u786e\u83b7\u53d6\u7279\u5b9a\u5143\u7d20\u7684\u65b9\u5f0f\u3002<\/p>\n<\/p>\n

\u7528\u6cd5<\/h4>\n<\/p>\n

var element = document.getElementById('elementId');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u793a\u4f8b<\/h4>\n<\/p>\n
\u8003\u8651\u4ee5\u4e0bHTML\u5143\u7d20\uff1a<\/p>\n<\/p>\n
<div id="uniqueID">\u5185\u5bb9<\/div><\/p>\n
<\/code><\/pre>\n<\/p>\n
JavaScript\u4e2d\uff0c\u4f60\u53ef\u4ee5\u8fd9\u6837\u83b7\u53d6\u8fd9\u4e2a\u5143\u7d20\uff1a<\/p>\n<\/p>\n
var div = document.getElementById('uniqueID');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e8c\u3001\u901a\u8fc7\u7c7b\u540d\u83b7\u53d6\u4e00\u7ec4\u5143\u7d20<\/h3>\n<\/p>\n
getElementsByClassName()<\/strong> \u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2aHTMLCollection\u5bf9\u8c61\uff0c\u5305\u542b\u4e86\u6240\u6709\u5177\u6709\u6307\u5b9a\u7c7b\u540d\u7684\u5143\u7d20\u3002\u8fd9\u4e2a\u65b9\u6cd5\u5bf9\u4e8e\u9700\u8981\u64cd\u4f5c\u7c7b\u4f3c\u9879\u76ee\u7684\u96c6\u5408\u975e\u5e38\u6709\u7528\u3002<\/p>\n<\/p>\n
\u7528\u6cd5<\/h4>\n<\/p>\n
var elements = document.getElementsByClassName('className');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u793a\u4f8b<\/h4>\n<\/p>\n
\u5047\u8bbe\u6211\u4eec\u6709\u591a\u4e2a\u5177\u6709\u76f8\u540c\u7c7b\u540d\u7684\u5143\u7d20\uff1a<\/p>\n<\/p>\n
<div class="classExample">\u7b2c\u4e00\u4e2a\u5143\u7d20<\/div><\/p>\n
<div class="classExample">\u7b2c\u4e8c\u4e2a\u5143\u7d20<\/div><\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f60\u53ef\u4ee5\u5229\u7528\u4ee5\u4e0bJavaScript\u4ee3\u7801\u83b7\u53d6\u6240\u6709\u8fd9\u4e9b\u5143\u7d20\uff1a<\/p>\n<\/p>\n
var divs = document.getElementsByClassName('classExample');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u901a\u8fc7\u6807\u7b7e\u540d\u83b7\u53d6\u4e00\u7ec4\u5143\u7d20<\/h3>\n<\/p>\n
getElementsByTagName()<\/strong> \u65b9\u6cd5\u540c\u6837\u8fd4\u56de\u4e00\u4e2aHTMLCollection\u5bf9\u8c61\uff0c\u5176\u4e2d\u5305\u542b\u5177\u6709\u6307\u5b9a\u6807\u7b7e\u540d\u7684\u6240\u6709\u5143\u7d20\u3002\u5b83\u9002\u7528\u4e8e\u83b7\u53d6\u5177\u6709\u76f8\u540c\u6807\u7b7e\u7684\u6240\u6709\u5143\u7d20\uff0c\u5982\u6240\u6709\u7684 <p><\/code> \u6216\u8005 <a><\/code> \u6807\u7b7e\u5143\u7d20\u3002<\/p>\n<\/p>\n
\u7528\u6cd5<\/h4>\n<\/p>\n
var elements = document.getElementsByTagName('tagName');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u793a\u4f8b<\/h4>\n<\/p>\n
\u5bf9\u4e8e\u4ee5\u4e0bHTML\uff1a<\/p>\n<\/p>\n
<p>\u7b2c\u4e00\u4e2a\u6bb5\u843d\u3002<\/p><\/p>\n
<p>\u7b2c\u4e8c\u4e2a\u6bb5\u843d\u3002<\/p><\/p>\n
<\/code><\/pre>\n<\/p>\n
\u83b7\u53d6\u6240\u6709 <p><\/code> \u5143\u7d20\u7684JavaScript\u4ee3\u7801\u5c06\u662f\uff1a<\/p>\n<\/p>\n
var paragraphs = document.getElementsByTagName('p');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001\u901a\u8fc7 CSS \u9009\u62e9\u5668\u83b7\u53d6\u5143\u7d20<\/h3>\n<\/p>\n
querySelector()<\/strong> \u548c querySelectorAll()<\/strong> \u65b9\u6cd5\u5141\u8bb8\u4f7f\u7528CSS\u9009\u62e9\u5668\u6765\u83b7\u53d6\u5355\u4e2a\u5143\u7d20\u6216\u5143\u7d20\u96c6\u5408\u3002querySelector()<\/strong> \u8fd4\u56de\u6587\u6863\u4e2d\u5339\u914d\u6307\u5b9aCSS\u9009\u62e9\u5668\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\uff0c\u800c querySelectorAll()<\/strong> \u8fd4\u56de\u6240\u6709\u5339\u914d\u5143\u7d20\u7684NodeList\u3002<\/p>\n<\/p>\n
\u7528\u6cd5<\/h4>\n<\/p>\n
var element = document.querySelector('.className'); \/\/ \u7c7b\u9009\u62e9\u5668<\/p>\n
var elements = document.querySelectorAll('p.className'); \/\/ \u6807\u7b7e\u4e0e\u7c7b\u7ed3\u5408\u7684\u9009\u62e9\u5668<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u793a\u4f8b<\/h4>\n<\/p>\n
\u5982\u6709\u4ee5\u4e0bHTML\u4ee3\u7801\uff1a<\/p>\n<\/p>\n
<div id="contAI<\/a>ner"><\/p>\n
  <div class="item">\u9879\u76ee 1<\/div><\/p>\n
  <div class="item active">\u9879\u76ee 2<\/div><\/p>\n
  <div class="item">\u9879\u76ee 3<\/div><\/p>\n
<\/div><\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8981\u83b7\u53d6\u5e26\u6709 'active' \u7c7b\u7684\u5143\u7d20\uff0c\u53ef\u4ee5\u4f7f\u7528\uff1a<\/p>\n<\/p>\n
var activeItem = document.querySelector('.item.active');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u800c\u83b7\u53d6\u6240\u6709\u7684 .item<\/code> \u7c7b\u5143\u7d20\uff1a<\/p>\n<\/p>\n
var items = document.querySelectorAll('.item');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u83b7\u53d6\u548c\u64cd\u4f5c\u8282\u70b9<\/h3>\n<\/p>\n
\u9664\u4e86\u5143\u7d20\uff0cDOM\u4e2d\u8fd8\u5305\u542b\u4e86\u5176\u4ed6\u7c7b\u578b\u7684\u8282\u70b9\uff0c\u5982\u6587\u672c\u8282\u70b9\u3001\u5c5e\u6027\u8282\u70b9\u7b49\u3002childNodes<\/strong> \u5c5e\u6027\u53ef\u4ee5\u83b7\u53d6\u4e00\u4e2a\u5143\u7d20\u7684\u6240\u6709\u5b50\u8282\u70b9\uff0c\u5305\u62ec\u5143\u7d20\u3001\u6587\u672c\u548c\u6ce8\u91ca\u8282\u70b9\uff0c\u8fd4\u56de\u4e00\u4e2aNodeList\u5bf9\u8c61\u3002<\/p>\n<\/p>\n
\u7528\u6cd5<\/h4>\n<\/p>\n
var childNodes = element.childNodes;<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u793a\u4f8b<\/h4>\n<\/p>\n
\u5bf9\u4e8e\u4ee5\u4e0bHTML\u5143\u7d20\uff1a<\/p>\n<\/p>\n
<div id="example"><\/p>\n
  \u6587\u672c\u8282\u70b9<\/p>\n
  <p>\u5143\u7d20\u8282\u70b9<\/p><\/p>\n
  <!-- \u6ce8\u91ca\u8282\u70b9 --><\/p>\n
<\/div><\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8981\u83b7\u53d6\u8fd9\u4e2a <div><\/code> \u5143\u7d20\u7684\u6240\u6709\u5b50\u8282\u70b9\uff1a<\/p>\n<\/p>\n
var example = document.getElementById('example');<\/p>\n
var exampleChildNodes = example.childNodes;<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001\u8282\u70b9\u904d\u5386\u548c\u8282\u70b9\u5c5e\u6027<\/h3>\n<\/p>\n
\u4f7f\u7528 childNodes<\/strong> \u83b7\u53d6\u8282\u70b9\u5217\u8868\u540e\uff0c\u901a\u5e38\u9700\u8981\u904d\u5386\u8fd9\u4e9b\u8282\u70b9\u5e76\u9488\u5bf9\u7279\u5b9a\u7c7b\u578b\u91c7\u53d6\u64cd\u4f5c\u3002\u8282\u70b9\u6709\u4e2a nodeType<\/strong> \u5c5e\u6027\uff0c\u901a\u8fc7\u8fd9\u4e2a\u5c5e\u6027\u53ef\u4ee5\u5224\u65ad\u8282\u70b9\u7684\u7c7b\u578b\u3002<\/p>\n<\/p>\n
\u904d\u5386\u8282\u70b9<\/h4>\n<\/p>\n
\u53ef\u4ee5\u4f7f\u7528\u5faa\u73af\u6765\u904d\u5386\u6bcf\u4e2a\u5b50\u8282\u70b9\uff0c\u5e76\u68c0\u67e5\u5176\u7c7b\u578b\uff0c\u6bd4\u5982\uff1a<\/p>\n<\/p>\n
for (var i = 0; i < childNodes.length; i++) {<\/p>\n
  if (childNodes[i].nodeType === 1) { \/\/ \u5143\u7d20\u8282\u70b9<\/p>\n
    \/\/ \u5bf9\u5143\u7d20\u8282\u70b9\u6267\u884c\u64cd\u4f5c<\/p>\n
  }<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8282\u70b9\u5c5e\u6027<\/h4>\n<\/p>\n
\u8282\u70b9\u5c5e\u6027\u53ef\u4ee5\u50cf\u64cd\u4f5c\u5bf9\u8c61\u4e00\u6837\u8fdb\u884c\u83b7\u53d6\u548c\u8bbe\u7f6e\uff1a<\/p>\n<\/p>\n
var attributeValue = element.getAttribute('attribute');<\/p>\n
element.setAttribute('attribute', 'newValue');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\n
\u603b\u7684\u6765\u8bf4\uff0c\u83b7\u53d6\u5143\u7d20\u548c\u8282\u70b9\u662fJavaScript\u64cd\u4f5cDOM\u7684\u6838\u5fc3<\/strong>\u3002\u8fd9\u4e9b\u57fa\u7840\u65b9\u6cd5\u4e3a\u5f00\u53d1\u8005\u63d0\u4f9b\u4e86\u4e30\u5bcc\u3001\u7075\u6d3b\u7684\u5de5\u5177\u96c6\u5408\uff0c\u7528\u4e8e\u8bbf\u95ee\u548c\u64cd\u4f5c\u9875\u9762\u5143\u7d20\u548c\u7ed3\u6784\uff0c\u662f\u5b9e\u73b0\u52a8\u6001\u548c\u4ea4\u4e92\u5f0fWeb\u5e94\u7528\u7684\u57fa\u7840\u3002\u638c\u63e1\u8fd9\u4e9b\u65b9\u6cd5\u4e0d\u4ec5\u80fd\u5e2e\u52a9\u5f00\u53d1\u8005\u5efa\u7acb\u5bf9DOM\u66f4\u52a0\u6df1\u523b\u7684\u7406\u89e3\uff0c\u800c\u4e14\u5728\u65e5\u5e38\u5f00\u53d1\u5de5\u4f5c\u4e2d\u4e5f\u4f1a\u5927\u653e\u5f02\u5f69\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
JavaScript\u4ee3\u7801\u5982\u4f55\u901a\u8fc7id\u83b7\u53d6\u5143\u7d20\uff1f<\/strong><\/p>\n
\u4f60\u53ef\u4ee5\u4f7f\u7528document.getElementById()<\/code>\u6765\u901a\u8fc7id\u83b7\u53d6\u5143\u7d20\u3002\u4f8b\u5982\uff0c\u5982\u679c\u4f60\u7684\u5143\u7d20\u6709\u4e00\u4e2a\u552f\u4e00\u7684id\u4e3a"myElement"\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u4ee3\u7801\u83b7\u53d6\u5230\u8be5\u5143\u7d20\uff1a<\/p>\n
let element = document.getElementById("myElement");\n<\/code><\/pre>\n
\u5982\u4f55\u901a\u8fc7\u7c7b\u540d\u83b7\u53d6\u5143\u7d20\uff1f<\/strong><\/p>\n
\u4f7f\u7528document.getElementsByClassName()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u6839\u636e\u7c7b\u540d\u83b7\u53d6\u5143\u7d20\u3002\u8fd9\u4e2a\u51fd\u6570\u5c06\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u6240\u6709\u5177\u6709\u6307\u5b9a\u7c7b\u540d\u7684\u5143\u7d20\u7684HTMLCollection\u5bf9\u8c61\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u4f60\u7684\u7c7b\u540d\u4e3a"myClass"\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\u83b7\u53d6\u6240\u6709\u5177\u6709\u8be5\u7c7b\u540d\u7684\u5143\u7d20\uff1a<\/p>\n
let elements = document.getElementsByClassName("myClass");\n<\/code><\/pre>\n
\u5982\u4f55\u901a\u8fc7\u6807\u7b7e\u540d\u83b7\u53d6\u5143\u7d20\uff1f<\/strong><\/p>\n
\u4f7f\u7528document.getElementsByTagName()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u6839\u636e\u6807\u7b7e\u540d\u83b7\u53d6\u5143\u7d20\u3002\u8fd9\u4e2a\u65b9\u6cd5\u5c06\u8fd4\u56de\u4e00\u4e2a\u5305\u542b\u6240\u6709\u5177\u6709\u6307\u5b9a\u6807\u7b7e\u540d\u7684\u5143\u7d20\u7684HTMLCollection\u5bf9\u8c61\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u4f60\u60f3\u83b7\u53d6\u6240\u6709\u7684\u6bb5\u843d\u5143\u7d20\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n
let paragraphs = document.getElementsByTagName("p");\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"\u83b7\u53d6\u5143\u7d20\u548c\u8282\u70b9\u662fJavaScript\u5f00\u53d1\u4e2d\u7684\u57fa\u7840\u64cd\u4f5c\uff0c\u53ef\u4ee5\u901a\u8fc7\u591a\u79cdDOM\uff08Document Object Mo […]","protected":false},"author":3,"featured_media":168906,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/168900"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=168900"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/168900\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/168906"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=168900"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=168900"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=168900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}