callbacks.has(callback)

返回值:Booleancallbacks.has(callback)

概述

確定是否提供的回調(diào)列表

參數(shù)

**callback**V1.7

用來搜索的回調(diào)。

示例

描述:

用?callbacks.has()?檢查是否回調(diào)列表中包含一個特定的回調(diào):

jQuery 代碼:

// 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