apply,call有什么用,怎么用我就不在这里介绍了,自己可以看看资料,可以告诉它们很有用就是.罗嗦的话不说,直接看实现代码吧
if (typeof(parseInt.apply) != 'function') { Function.prototype.apply = function (obj, argu) { var s; if (obj) { obj.constructor.prototype._caller = this; s = "obj._caller"; } else { s = "this"; } var argus = new Array(); for (var i=0;i<argu.length;i++) argus[i] = "argu[" + i + "]"; eval("var r = " + s + "(" + argus.join(",") + ");"); return r; }; Function.prototype.call = function (obj) { var argu = new Array(); for (var i=1;i<arguments.length;i++) argu[i-1] = arguments[i]; return this.apply(obj, argu); }; }
先实现apply,再用apply实现call.加上parseInt.apply来判断看是否是高版本,已经支持apply和call.