# jQuery UI addClass

## Overview

[edit]

### addClass( class, [duration] )

Adds the specified class to each of the set of matched elements with an optional transition between the states.

### Dependencies

- Effects Core

### Example

- Demo
- View Source

Adds the class 'selected' to the matched elements with a one second transition.

    $("p").click(function () {
          $(this).addClass("selected", 1000);
        });

    <!DOCTYPE html>
    <html>
    <head>
      <link type="text/css" href="http://jqueryui.com/latest/themes/base/jquery.ui.all.css" rel="stylesheet" />
      <script type="text/javascript" src="http://jqueryui.com/latest/jquery-1.4.2.js"></script>
      <script src="http://ui.jquery.com/latest/ui/effects.core.js"></script>
    <style type="text/css">
      p { cursor: pointer; font-size: 1.2em; }
      .selected { color:red; }
    </style>
      <script type="text/javascript">
      $(document).ready(function(){
        $("p").click(function () {
          $(this).addClass("selected", 1000);
        });
      });
      </script>
    </head>
    <body style="font-size:62.5%;">
      <p>Click me to add a 'selected' class.</p>
    <p>Click me to add a 'selected' class.</p>
    <p>Click me to add a 'selected' class.</p>
    </body>
    </html>

## Arguments

- ### class

  Type:
    String

  One CSS class to add to the elements.

- ### duration

  Type:
    String, Number
  Optional

  A string representing one of the three predefined speeds ("slow", "normal", or "fast") or the number of milliseconds to run the animation (e.g. 1000).