How to determine whether a class exists in jquery

How to determine whether a class exists in jquery: 1. Use the [is('.classname')] method; 2. Use the [hasClass('classname')] method, the code is [$('div' ).hasClass('redColor')].

The operating environment of this tutorial: windows7 system, jquery3.2.1 version. This method is suitable for all brands of computers.

Methods for whether class exists in jquery:

There are two methods you can use in jquery to determine whether an element contains a certain class (class). Both methods have the same functionality. The 2 methods are as follows:

• is('.classname')

• hasClass('classname')

The following is an example of whether a div element contains a redColor:

1. Use the is('.classname') method

$('div').is('.redColor')

2. Use hasClass('classname') method (note that the lower version of jquery may be hasClass('.classname'))

$('div').hasClass('redColor')

The following is an example of detecting whether an element contains a redColor class, When included, change its class to blueColor.

.redColor {
background:red;
}
.blueColor {
background:blue;
}




jQuery check if an element has a certain class
This is a div tag with class name of "redColor"

is('.redColor') hasClass('.redColor') reset

$("#isTest").click(function () { if($('div').is('.redColor')){ $('div').addClass('blueColor'); } }); $("#hasClassTest").click(function () { if($('div').hasClass('redColor')){ $('div').addClass('blueColor'); } }); $("#reset").click(function () { location.reload(); });

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