How does jquery determine whether a dom element exists?

Jquery method to determine whether a dom element exists: 1. Use the "$("#id")" statement to obtain the dom element object through the id attribute; 2. Use the "element object.length" statement to obtain the length value; 3. Determine whether the obtained length value is greater than 0. If it is greater, it exists, otherwise it does not exist.

The operating environment of this tutorial: windows7 system, jquery1.10.2 version, Dell G3 computer.

jquery determines whether the dom element exists

Implementation idea:

• Pass in the js file The id attribute gets the dom element object

• Use the length attribute to get the length of the dom element object, If the element exists, length=1

• Determine whether the length value is greater than 0

if($("#id").length >0){
//元素存在，则length=1
 alert("元素存在");
}else{
 
  //元素不存在，则length=0
 alert("元素不存在");
}

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