| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455 | <!DOCTYPE html><html lang="en"><head>  <meta charset="UTF-8">  <meta http-equiv="X-UA-Compatible" content="IE=edge">  <meta name="viewport" content="width=device-width, initial-scale=1.0">  <title>Document</title></head><body>  <div id="div1" class="content">Hello</div>  <div class="content">word</div>  <ul id="ul1">    <li>1</li>    <li>2</li>    <li>3</li>  </ul>  <ul id="ul2">    <li>4</li>    <li>5</li>    <li>6</li>  </ul>  <script>    // var div1 = document.getElementById('div1')    // var content = document.getElementsByClassName('content')    // var div2 = document.getElementsByTagName('div')    /* querySelector 获取元素  但是只获取第一个元素 */    var div1 = document.querySelector('#div1')    console.log(div1)    var content = document.querySelector('.content')    console.log(content)    var div2 = document.querySelector('div')    console.log(div2)    /* querySelectorAll 查找所有满足条件的元素   */    /* nodeList 类数组  不是真正的数组  不太具备数组当中的方法 */    var aLi = document.querySelectorAll('li')    console.log(aLi)    var a = []    console.log(a)    for (var i = 0; i < aLi.length; i++) {      aLi[i].onclick = function(){        console.log(this.innerHTML)      }    }    var ul2 = document.querySelector('#ul2')    var bLi = ul2.querySelectorAll('li')    console.log(bLi)  </script></body></html>
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