callbacks.lock()实例分享

　　callbacks.lock()

　　描述: 锁定回调列表的当前状态。

　　添加的版本: 1.7callbacks.lock()

　　这个方法不接受任何参数

　　此方法返回绑定它的那个回调对象(this).

　　如果回调对象被创建，用"memory"标志作为它的参数，绑定函数可能会在回调列表中被锁定后增加并且触发。

　　例子:

　　Example: 用 callbacks.lock() 锁定一个回调列表，以避免进一步的修改列表状态 :

　　// a sample logging function to be added to a callbacks list

　　var foo = function( value ) {

　　console.log( "foo:" + value );

　　};

　　var callbacks = $.Callbacks();

　　// add the logging function to the callback list

　　callbacks.add( foo );

　　// fire the items on the list, passing an argument

　　callbacks.fire( "hello" );

　　// outputs "foo: hello"

　　// lock the callbacks list

　　callbacks.lock();

　　// try firing the items again

　　callbacks.fire( "world" );

　　// as the list was locked, no items

　　// were called, so "world" isn"t logged

　　Example: Use callbacks.lock() to lock a callback list with "memory," and then resume using the list:

　　<!DOCTYPE html>

　　<html>

　　<head>

　　</head>

　　<body>

　　<script>// simple function for logging results

　　var log = function( value) {

　　$( "#log" ).append( "<p>" + value + "</p>" );

　　};

　　// two sample functions to be added to a callbacks list

　　var foo = function( value ) {

　　log( "foo: " + value );

　　};

　　var bar = function( value ) {

　　log( "bar: " + value );

　　};

　　// create the callbacks object with the "memory" flag

　　var callbacks = $.Callbacks( "memory" );

　　// add the foo logging function to the callback list

　　callbacks.add( foo );

　　// fire the items on the list, passing an argument

　　callbacks.fire( "hello" );

　　// outputs "foo: hello"

　　// lock the callbacks list

　　callbacks.lock();

　　// try firing the items again

　　callbacks.fire( "world" );

　　// as the list was locked, no items were called,

　　// so "foo: world" isn't logged

　　// add the foo function to the callback list again

　　callbacks.add( foo );

　　// try firing the items again

　　callbacks.fire( "silentArgument" );

　　// outputs "foo: hello" because the argument value was stored in memory

　　// add the bar function to the callback list

　　callbacks.add( bar );

　　callbacks.fire( "youHadMeAtHello" );

　　// outputs "bar: hello" because the list is still locked,

　　// and the argument value is still stored in memory

　　</script>

　　</body>

　　</html>

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