js时间差 倒计时

function share_data_time() {
		window.setTimeout("share_data_time()", 1000);
	    //毕业时间
	    BirthDay = new Date("5/11/2018 00:00:00");
	    //获取当前时间
	    today = new Date();
	    timeold = (today.getTime() - BirthDay.getTime()); //总豪秒数
	    secondsold = Math.floor(timeold / 1000);          //总秒数
	    e_daysold = timeold / (24 * 60 * 60 * 1000);
	    daysold = Math.floor(e_daysold);                 //相差天数
	    e_hrsold = (e_daysold - daysold) * 24;
	    hrsold = Math.floor(e_hrsold);                   //相差小时数
	    e_minsold = (e_hrsold - hrsold) * 60;
	    minsold= Math.floor(e_minsold)                   //相差分钟数
	    seconds = Math.floor((e_minsold - minsold) * 60);  //相差秒数
	    //将所获取的时间拼接到一起，再把值显示到页面
	    share_time.innerHTML = "已毕业:" + daysold + "天" + hrsold + "小时" + minsold + "分" + seconds + "秒";
	}
	share_data_time();