构造函数定义类的问题

Question

/我是按书上打出来的 为什么显示range is not defined,不太明白，我也没得range没定义，但不知道哪里错了/

function Range(from,to){    this.from=from;  
    this.to=to;
}

Range.prototype={    includes:function(x){  
        return this.from<=x&&x<=this.to; 
    },    foreach:function(f){        for(var x=Math.ceil(this.form);x<=this.to;x++)f(x); 
    },    toString:function(){        return "("+this.form+"..."+this.to+")";  
    }
};var r=range(1,3);  //r.includes(2);  //

Answer 1

大哥是不是少了个new，而且是大写Rvar r = new Range(1,3);