jQuery callbacks.empty() Method

Last Updated : 14 Jul, 2020

The callbacks.empty() method in jQuery is used to remove all the callbacks from a list. It returns the Callbacks object onto which it is attached.

Syntax:

callbacks.empty()

Parameters: It does not accept any parameter.

Return Value: This method returns the Callbacks object onto which it is attached.

Below examples illustrate the callbacks.empty() method in jQuery:

Example 1: In this example, the fun1 function is first added to the callbacks list and all the callbacks present are executed in the list with a given argument. The callbacks.empty() method is executed to empty the list. The second function fun2 is added and the callbacks list is executed again. This demonstrates the emptying of the list after adding the first function.

html

<!DOCTYPE HTML> 
<html> 
  
<head> 
    <title> 
        JQuery callbacks.empty() method 
    </title> 
  
    <script src= 
"https://code.jquery.com/jquery-3.5.0.js"> 
    </script> 
</head> 
  
<body style="text-align:center;"> 
  
    <h1 style="color:green;"> 
        GeeksForGeeks 
    </h1> 
  
    <p> 
        JQuery | callbacks.empty() method 
    </p> 
  
    <button onclick="Geeks();"> 
        click here 
    </button> 
  
    <p id="output"></p> 
  
    <script> 
        var output = document.getElementById("output"); 
        var res = ""; 
  
        // Initialize a callback list 
        var callbacks = jQuery.Callbacks(); 
  
        function Geeks() { 
              
            // First function to be added to the list 
            var fun1 = function (val) { 
                res = res + "This is function 1 and" + 
                    " value passed is " + val + "<br>"; 
            }; 
  
            // Second function to be added to the list 
            var fun2 = function (val) { 
                res = res + "This is function 2 and" + 
                    " value passed is " + val + "<br>"; 
            }; 
  
            // Adding the first function 
            callbacks.add(fun1); 
  
            // Calling the first function 
            callbacks.fire("GFG_1"); 
  
            // Clearing the callback list 
            callbacks.empty(); 
  
            // Adding the second function 
            callbacks.add(fun2); 
  
            // Calling the first function 
            callbacks.fire("GFG_2"); 
  
            output.innerHTML = res; 
        }  
    </script> 
</body> 
  
</html> 

Output:

Example 2: This example provides a button to empty the callback list and then add the given function to see the result of emptying the callbacks list.

html

<!DOCTYPE HTML> 
<html> 
  
<head> 
    <title> 
        JQuery | callbacks.empty() method 
    </title> 
  
    <script src= 
"https://code.jquery.com/jquery-3.5.1.min.js"> 
    </script> 
</head> 
  
<body style="text-align:center;"> 
  
    <h1 style="color:green;"> 
        GeeksForGeeks 
    </h1> 
  
    <p> 
        JQuery | callbacks.empty() method 
    </p> 
  
    <button onclick="Geeks();"> 
        click here 
    </button> 
  
    <button onclick="empty();"> 
        empty 
    </button> 
      
    <p id="output"></p> 
  
    <script> 
        var output = document.getElementById("output"); 
        var res = ""; 
  
        // Initialize a callback list 
        var callbacks = jQuery.Callbacks(); 
  
        function empty() { 
  
            // Clear the callback list 
            callbacks.empty(); 
        } 
  
        // Function to add and fire callbacks  
        function Geeks() { 
  
            // Function to be added to the list 
            var fun1 = function (val) { 
                res = res + "This is function 1 and" + 
                    " value passed is " + val + "<br>"; 
            }; 
  
            // Adding the given function 
            callbacks.add(fun1); 
  
            // Calling the function with value 
            callbacks.fire("GFG_1"); 
  
            output.innerHTML = res; 
        }  
    </script> 
</body> 
  
</html> 