Question

/ *请查看此代码，请告诉我们如何找不到。课程＆＃34; myDIV＆＃34; 我已尝试使用getelementbyid和childNodes.length，但没有任何工作 * /

<div id="example">First div element with class="example"
    <div class="fexample">First div element with class="example"
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    </div>
    </div>
    <script>
     function myFunction() {
     var a = document.getElementsByClassName("myDIV");
     document.getElementById("demo").innerHTML = a.length;
    }
    </script>
        </body>

Answer 1

使用document.querySelectorAll()构建包含该类的所有元素的列表，使用.length属性返回金额。

＆＃13;

var elements = document.querySelectorAll('.myDIV');
console.log(elements.length)

＆＃13;

<div id="example">First div element with class="example"
    <div class="fexample">First div element with class="example"
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    <div class="myDIV">
      <p>First p element in div.</p>
      <p>Another p element in div.</p>
    </div>
    </div>
    </div>

＆＃13;

Answer 2

我认为这就是你要找的东西。

var a = document.querySelectorAll('.myDIV');
a.length;

怎么找不到。名为＆＃34; myDIV＆＃34;的课程

2 个答案: