jquery(zepto) when then 使用

1. 作用

when和then主要是为了解决一个或多个异步请求实现同一回调。

2. 实例

(function($){    var asyncHandlerA = function() {        var deferred = $.Deferred();        setTimeout(function() {            console.log("asyncHandlerA finished....");            deferred.resolve("AAAAAAA");        }, 3000);        return deferred.promise();    };    var asyncHandlerB = function() {        var deferred = $.Deferred();        setTimeout(function() {            console.log("asyncHandlerB finished....");            deferred.resolve("BBBBBBB");        }, 5000);        return deferred.promise();    };    var asyncHandlerC = function() {        var deferred = $.Deferred();        setTimeout(function() {            console.log("asyncHandlerC finished....");            deferred.resolve("CCCCCCCCC");        }, 8000);        return deferred.promise();    };    $.when(asyncHandlerA(), asyncHandlerB(), asyncHandlerC()).done(function(resA, resB, resC){        console.log("resA = " + resA + ", resB = " + resB + ", resC = " + resC);    });})(jQuery);