javascript 使用链式结构

var Dog = function(name,color){
 this.name=name||"";
 this.color=color||"";
};
Dog.prototype.setName = function(name){
 this.name = name;
 return this;
};
Dog.prototype.setColor = function(color){
 this.color=color;
 return this;
};
Dog.prototype.yell = function(){
 alert(this.name+this.color);

return this;
};
var dog = new Dog();
dog.setName("hhh").setColor("red").yell();