Function.prototype.bind = function(obj) { var _this = this; return function() { _this.apply(obj,arguments); } }

var a = function(){ alert(this.title) }.bind(document); a();

function myalert() { this.title = 'hello world'; this.init = function() { $("#xxx").click(this.close.bind(this)); } this.close = function() { alert(this.title) } }

<P style="PADDING-BOTTOM: 0px; LINE-HEIGHT: 22px; MARGIN-TOP: 0px; FONT-FAMILY: 微软雅黑, 宋体, 'Trebuchet MS', Tahoma, Arial, sans-serif; MARGIN-BOTTOM: 10px; COLOR: rgb(34,34,34); FONT-SIZE: 14px; PADDING-TOP: 0px" class=p1>var a  = new myalert();</P><P style="PADDING-BOTTOM: 0px; LINE-HEIGHT: 22px; MARGIN-TOP: 0px; FONT-FAMILY: 微软雅黑, 宋体, 'Trebuchet MS', Tahoma, Arial, sans-serif; MARGIN-BOTTOM: 10px; COLOR: rgb(34,34,34); FONT-SIZE: 14px; PADDING-TOP: 0px" class=p1>a.init();</P>