How to determine whether an object exists in jquery

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

The operating environment of this tutorial: windows10 system, jquery2.2.4 version. This method is suitable for all brands of computers.

(Learning video sharing: javascript video tutorial)

Jquery method to determine whether an object exists:

The specific method is as follows ;

If the following jQuery code is used to determine whether an object exists, it cannot be used.

if($("#id")){
  //...
}else{
  //...
}

Because $("#id") will return object regardless of whether the object exists.

Correct use to determine whether the object exists should be:

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

Use the jQuery object's property length to determine, if > 0, it exists.

or

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

Or directly use the native Javascript code to judge:

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

Related recommendations: js tutorial

The above is the detailed content of How to determine whether an object exists in jquery. For more information, please follow other related articles on the PHP Chinese website!