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                        /前端开发
                        
                            /jQuery
                        
                        /jQuery源码解析（架构与依赖模块）

callback回调问题（输出的结果为什么是这样）

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script src="http://img1.sycdn.imooc.com//down/540812440001e40e00000000.js" type="text/javascript"></script>
<title></title>
</head>
<body>

<script type="text/javascript">

function show(data) {
$("body").append('<li>' + data + '</li>')
}

function fn1(value) {
show("fn1 says: "+value+'</br>');
}

function fn2(value) {
fn1("fn2 says: " + value+'</br>');
return false;
}
function fn3(value) {
fn1("fn3 says: " + value+'</br>');
return false;
}

var callbacks = $.Callbacks();

callbacks.add(fn1);
callbacks.fire("foo!");        //输出fn1 says:foo!
callbacks.add(fn2);
callbacks.fire("too!");    //输出 fn1 says:too!   fn1 says:fn2 says:too!
callbacks.add(fn3);
callbacks.fire("bar!");   //输出fn1 says:bar!   fn1 says:fn2 says:bar!    fn1 says:fn3 says:bar!

</script>

</body>
</html>