数值的扩展

1、判断关键字

isFinite():

(function (global) {

var global_isFinite = global.isFinite;

object.defineProperty(Number,"isFinite",{
    value : function isFinite(value) {
       return typeof value === "number" && global_isFinite(value);
    },
    configurable:true,
    enumerable:false,
    writable:true
})

})(this);

isNaN():

(function (global) {

var global_isNaN = global.isNaN;

object.defineProperty(Number,"isNaN",{
    value : function isNaN(value) {
       return typeof value === "number" && global_isNaN(value);
    },
    configurable:true,
    enumerable:false,
    writable:true
})

})(this);

2、Number.parseInt(),Number.parseFloat()

3、Number.isInteger()