js面向对象编程总结

var Circle = function() { var obj = new Object(); obj.PI = 3.14159; obj.area = function( r ) {  return this.PI * r * r; } return obj;}var c = new Circle();alert( c.area( 1.0 ) );

function Circle(r) {  this.r = r;}Circle.PI = 3.14159;Circle.prototype.area = function() { return Circle.PI * this.r * this.r;}var c = new Circle(1.0); alert(c.area());

var Circle={ "PI":3.14159, "area":function(r){   return this.PI * r * r;  }};alert( Circle.area(1.0) );

var Circle=function(r){  this.r=r;}Circle.PI = 3.14159; Circle.prototype={ area:function(){  return this.r*this.r*Circle.PI; }}var obj=new Circle(1.0);alert(obj.area())

var show={  btn:$('.div1'),  init:function(){   var that=this;   alert(this);   this.btn.click(function(){     that.change();     alert(this);    })  },  change:function(){   this.btn.css({'background':'green'});  } } show.init();