示例

描述:

用 callbacks.has() 检查是否回调列表中包含一个特定的回调:

jQuery 代码:

// 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