扩展Date的DateDiff方法--日期差

Date.prototype.DateDiff = function(after){
    var diffDay;
    var beforeDate = new Date(this).format("yyyy-MM-dd");
    beforeDate = beforeDate.split('-');
    beforeDate = new Date(beforeDate[1] + '-' + beforeDate[2] + '-' + beforeDate[0]).toLong();
    console.log("beforeDate");
    console.log(beforeDate);
    var afterDate = new Date(after).format("yyyy-MM-dd");
    afterDate = afterDate.split("-");
    afterDate = new Date(afterDate[1] + '-' + afterDate[2] + '-' + afterDate[0]).toLong();
    console.log("afterDate");
    console.log(afterDate);
    diffDay = parseInt(Math.abs(afterDate - beforeDate) / 1000 / 60 / 60 /24);
    console.log("diffDay");
    console.log(diffDay);
    return diffDay + 1 +"天";
};