1.第一种方式：原型链
代码：
function SuperType(){
this.property = true;
}
SuperType.prototype.getSuperValue = function(){
return this.property;
};
function SubType(){
this.subproperty = false;
}
//继承了 SuperType
SubType.prototype = new SuperType();
SubType.prototype.getSubValue = function(){
return this.subproperty
};
var instance = new SubType();
2.第二种方式：借用构造函数
funtion SuperType(){
this.colors = ["red","blue","green"];
}
function SubType(){
//继承了SuperType
SuperType.call(this);
}