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How to determine if an element exists with JQuery

藏色散人Original: 2018-12-13 16:15:4515105browse

JQuery determines whether an element exists. We can use the jQuery .length property to achieve this. When an event is triggered when a specific element exists in the DOM, you can use the jQuery .length property to determine whether the element exists.

Below we will combine a simple code example to introduce to you the specific method of JQuery to determine whether an element exists.

The code example is as follows:

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>JQuery判断元素是否存在的示例</title>
    <script src="https://code.jquery.com/jquery-1.12.4.min.js"></script>
    <script type="text/javascript">
       $(function () {
           $("button").click(function () {
               if($("#myDiv").length) {
                   alert("元素已存在");
               }
                   else {
                       alert("元素不存在");
                   }

           });
       });
    </script>
</head>
<body>
</body>
<div id="myDiv"></div>
<p>点击下面的按钮检查元素</p>
<button>检查元素</button>
</html>

In the above code, we added a click event to the button. When the button button is clicked, the method of judging the element will be triggered. If the specified div exists, it will A prompt of "Element already exists" pops up, otherwise a prompt of "Element does not exist" pops up.

The judgment result is as follows:

When there is a div, click the button to display the following picture:

How to determine if an element exists with JQuery

When the div does not exist, click the button to display the following image:

How to determine if an element exists with JQuery

Note: The length attribute contains the number of elements in the jQuery object.

This article is an introduction to JQuery to determine whether an element exists. It is also very simple. I hope it will be helpful to friends in need!

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