How to determine if id exists in jquery

How jquery determines whether an id exists: You can use the length attribute of the jquery object to determine, such as [if($("#id").length>0){}else{}], if length> 0 means that the id exists, otherwise it means that the id does not exist.

The operating environment of this tutorial: Windows 10 system, jquery version 2.2.4. This method is suitable for all brands of computers.

(Learning video sharing: jquery video tutorial)

The judgment method is as follows:

Use the length attribute of the jQuery object to judge, if > 0 Just exists.

if($("#id").length>0){}else{}

or

if($("#id")[0]){} else {}

or directly use the native Javascript code to determine:

if(document.getElementById("id")){} else {}

Example:

if ($('#myElement').length > 0) { 
	// 存在
    document.write("id 为 myElement 元素存在");
} else {
	document.write("id 为 myElement 元素不存在");
}
document.write("<br>");
if ($(&#39;#xxx&#39;).length > 0) { 
	// 存在
    document.write("id 为 xxx 元素存在");
} else {
	document.write("id 为 xxx 元素不存在");
}

Result:

id 为 myElement 元素存在
id 为 xxx 元素不存在

Related recommendations: js tutorial

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