javascript - 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R
var r = new Range(1,3);

Answer 2

肯定是R没大写了...
JS的函数名大小写敏感，PHP的不敏感，有区别哦

Answer 3

请下次注意好编辑描述和代码

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 = new Range(1, 3); //
alert(r.includes(2)); //
alert(r); 

这是你要的内容,对比一下区别