问如何检查一个数字是浮点数还是整数？

Object.prototype.getConstructorName = function () {

   var str = (this.prototype ? this.prototype.constructor : this.constructor).toString();

   var cname = str.match(/function\s(\w*)/)[1];

   var aliases = ["", "anonymous", "Anonymous"];

   return aliases.indexOf(cname) > -1 ? "Function" : cname;

}

new Array().getConstructorName();  // returns "Array"

(function () {})().getConstructorName(); // returns "Function

function Square(){

    this.className = "Square";

    this.corners = 4;

}

var MySquare = new Square();

console.log(MySquare.className); // "Square"