jQuery callbacks.add() 方法

jQuery callbacks.add()方法用于将回调或回调集合添加到回调列表中。此方法返回它所附加的回调对象（this）。

句法：

callbacks.add(callbacks)

参数：

• callbacks：这个参数包含一个函数或一个函数数组，它们将被添加到回调列表中。

示例 1：该方法在回调中添加了一个方法fun1()并调用它。

  

    
        jQuery callbacks.add() method
    
  
    
    

  

    
        GeeksForGeeks
    
      
    
      
    
        click here
    
      
    
      
    
        var el_up = document.getElementById("GFG_UP");
        var el_down = document.getElementById("GFG_DOWN");
        el_up.innerHTML = 
                    "JQuery | callbacks.add() method";
        var res = "";
          
        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>";
            };
            var callbacks = jQuery.Callbacks();
            callbacks.add(fun1); //Aadding the func1
            callbacks.fire("GFG_1"); // Calling the fun1
            el_down.innerHTML = res;
        } 
    

  

输出：

示例 2：此示例将方法fun1()和fun2() 添加到回调中，然后调用它们。请注意，在第二次调用fire()方法时，它使用相同的参数“GFG_2”调用这两个函数。

  

    
        jQuery callbacks.add() method
    
      
    
    

  

    
        GeeksForGeeks
    
      
    
      
    
        click here
    
      
    
      
    
        var el_up = document.getElementById("GFG_UP");
        var el_down = document.getElementById("GFG_DOWN");
        el_up.innerHTML = 
                "JQuery | callbacks.add() method";
        var res = "";
  
        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>";
            };
  
            var callbacks = jQuery.Callbacks();
  
            // Adding the function 1
            callbacks.add(fun1);
  
            // Calling the function 1
            callbacks.fire("GFG_1");
  
            // Adding the function 2
            callbacks.add(fun2); 
  
            // Calling the function 2
            callbacks.fire("GFG_2"); 
  
            // res of the both functions
            el_down.innerHTML = res; 
        } 
    

  

输出：