Description

The .addClass() method adds one or more classes to the selected elements.

This method does not remove existing class attributes, it only adds one or more values to the class attribute.

Tip: To add more than one class, separate the class names with space.

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This method has the form:

.addClass(class)

Parameter	Description
class	(required) Specifies one or more class names to be added

Return Value

This form returns a jQuery object.

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Add Class Using a Function

Using a function to add classes to selected elements.

This method has the alternate form:

.addClass(function(index,oldclass))

Parameter	Description
function(index, oldclass)	(required) Specifies a function that returns one or more class names to be added. index - (optional) Receives the index position of the selector oldclass - (optional) Receives the old class value of the selector

Return Value

This form returns a jQuery object.

Examples

Add a class to the first p element:

$("button").click(function(){
  $("p:first").addClass("intro");
});