off

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小牛编辑

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2023-12-01

描述 (Description)

此事件从对象中删除回调函数或所有事件。

语法 (Syntax)

object.off(event, callback function, [context])

参数 (Parameters)

event - 它绑定一个对象。
callback - 它是对代码的引用。
context - 它是一个可以传递给回调函数的对象。

例子 (Example)

<!DOCTYPE html>
<html>
   <head>
      <title>Event Off Example</title>
      <script src = "https://code.jquery.com/jquery-2.1.3.min.js"
         type = "text/javascript"></script>
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js"
         type = "text/javascript"></script>
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js"
         type = "text/javascript"></script>
   </head>
   <body>
      <script type = "text/javascript">
         //Here creating an object 'myVal' and extending with Backbone.Events method
         var myVal = _.extend({name:'hello'}, Backbone.Events);
         var myFunc = function () {
            document.write('Hello');
         };
         var myFunc1 = function () {
            document.write('Welcome to xnip');
         };
         // The on() method will bind the callback function to objects 
         // 'myFunc' and 'myFunc1'
         myVal.on('log',myFunc);
         myVal.on('log',myFunc1);
         document.write('Before using off event, values will be: ');
         // trigger() method callbacks for the given event and display the text 
         // defined in the 'myFunc' and 'myFunc1' functions
         myVal.trigger('log');
         //The off() method removes the callback for 'myFunc' and logs only 
         // text of 'myFunc1'
         myVal.off('log',myFunc);
         document.write("<br>");
         document.write('After using off event, values will be: ');
         myVal.trigger('log');
      </script>
   </body>
</html>