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返回值:Boolean callbacks.has(callback)

概述

確定是否提供的回撥列表

參數

callback V1.7

用來搜索的回撥。

示例

描述:

用 callbacks.has() 檢查是否回撥列表中包含一個特定的回撥:

jQuery 程式碼:

// a sample logging function to be added to a callbacks list
var foo = function( value1, value2 ){
    console.log( 'Received:' + value1 + ',' + value2 );
}

// a second function which will not be added to the list
var bar = function( value1, value2 ){
    console.log( 'foobar');
}

var callbacks = $.Callbacks();

// add the log method to the callbacks list
callbacks.add( foo );

// determine which callbacks are in the list

console.log( callbacks.has( foo ) ); // true
console.log( callbacks.has( bar ) ); // false