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jQuery | undelegate() with Examples

The undelegate() method is an inbuilt method in jQuery which is used to remove the specified event handler from the selected element.

Syntax:

$(selector).undelegate(selector, event, function)

Parameters: This method accepts three parameters as mentioned above and described below:



  • selector: It is an optional parameter which is used to specify the selector from which event will remove.
  • event: It is an optional parameter which is used to specify the name of the event type on the selector.
  • function: It is an optional parameter which is used to specify the name of the handler function to remove.

Return Value: This method returns the selected element with specified changes made by undelegate() method.

Below examples illustrate the undelegate() method in jQuery:

Example 1: This example does not contain any parameters.

<!DOCTYPE html>
<html>
    <head>
        <title>The undelegate Method</title>
        <script src=
        </script>
          
        <!-- jQuery code to show the working of this method -->
        <script>
            $(document).ready(function() {
                $("body").delegate("p", "click", function() {
                    $(this).css("font-size", "25px");
                });
                $("button").click(function() {
                    $("body").undelegate();
                });
            });
        </script>
        <style>
            div {
                width: 300px;
                height: 100px;
                background-color: lightgreen;
                padding: 20px;
                font-weight: bold;
                font-size: 20px;
                border: 2px solid green;
            }
            button {
                margin-top: 10px;
            }
        </style>
    </head>
    <body>
        <div>
            <!-- click on this p element -->
            <p>Welcome to GeeksforGeeks!.</p>
        </div>
        <!-- click on this button to remove the 
        event handler -->
        <button>Remove...!</button>
    </body>
</html>                                            

Output:
Before click anywhere:

After click on the paragraph:

Note: First click on the button and then click on the paragraph, then no changes occur.

Example 2: This example contains all parameters.

<!DOCTYPE html>
<html>
    <head>
        <title>The undelegate Method</title>
        <script src=
        </script>
          
        <!-- jQuery code to show the working of this method -->
        <script>
            $(document).ready(function() {
                $("body").delegate("div", "click", function() {
                    $(this).animate({
                        height: "+=100px"
                    });
                    $(this).animate({
                        width: "+=100px"
                    });
                });
                $("button").click(function() {
                    $("body").undelegate("div", "click");
                });
            });
        </script>
        <style>
            div {
                width: 30px;
                height: 30px;
                background-color: green;
            }
            button {
                margin-top: 10px;
            }
        </style>
    </head>
    <body>
        <div></div>
        <!-- click on this button -->
        <button>Click here..!</button>
    </body>
</html>

Output:
Before clicking anywhere:

After clicking on the div element get resized.

Note: If click on the button and then click on the div element then no change in the size will take place.



This article is attributed to GeeksforGeeks.org

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