调用方法

var _TimeCountDown = new TimeCountDown("sttime1",{ 
startTime:'2016-07-30 10:07:55',	//开始时间
endTime:'2016-07-30 10:08:00',	//结束时间	
timeCallBack:"timeOverfun", //回调函数
});

countDown.js

/**
 * @author wanghaitao
 * @param sttime1 id
 * @param startTime 开始时间
 * @param endTime 结束时间
 * @param timeCallBack 回调函数
 * 
 * 	var _TimeCountDown = new TimeCountDown("sttime1",{	
		startTime:'2016-07-30 10:07:55',		//开始时间
		endTime:'2016-07-30 10:08:00',			//结束时间		
		timeCallBack:"timeOverfun",  //回调函数
	});
 */


(function(window,undefined){
	var TimeCountDown = function(container, params){
		if(!(this instanceof TimeCountDown)) return new TimeCountDown(container, params);
		
	   var defaults = {
		 		endTime:'',			//title
				startTime:'',		//请传入ID，或DOM对象
				Lid:'',
				leftTitle:"倒计时:",//左侧名称
				colonStat:false,//是否把小时分转换成：
				timeCallBack:null	//关闭执行的回调函数	 
	   }
	   params = params || {};
       var originalParams = {};
       for (var param in params) {
        
            if (typeof params[param] === 'object' && params[param] !== null && !(params[param].nodeType || params[param] === window || params[param] === document || (typeof Dom7 !== 'undefined' && params[param] instanceof Dom7) || (typeof jQuery !== 'undefined' && params[param] instanceof jQuery))) {
                originalParams[param] = {};
                for (var deepParam in params[param]) {
                    originalParams[param][deepParam] = params[param][deepParam];
                }
            }
            else {
                originalParams[param] = params[param];
            }
       }
	   for (var def in defaults) {
            if (typeof params[def] === 'undefined') {
                params[def] = defaults[def];
            }
            else if (typeof params[def] === 'object') {
                for (var deepDef in defaults[def]) {
                    if (typeof params[def][deepDef] === 'undefined') {
                        params[def][deepDef] = defaults[def][deepDef];
                    }
                }
            }
      }
       var s = this;
        // Params
        s.params = params;
	 	s.container = container;
        s.currentBreakpoint = undefined;
		s.calculateTime = function(){
			var startTime = s.vert(this.params.startTime);				
			var endTime = s.vert(this.params.endTime);
			var time = endTime - startTime;  //时间差的毫秒数 ;
			return time;
		}
		s.vert = function(time){
			if(typeof time == "undefined" || time==""){
				return false;
			}
			var strtime = (time).replace(/-/g,"/");
			var date1 = new Date(strtime);
			return parseInt(date1.getTime());			
		}
		s.nTime = s.calculateTime();
		s.countdown();

	};
	
	TimeCountDown.prototype = {
			countdown:function(){
					var interval = 1000; //毫秒		
					var time;
				 	this.nTime = this.nTime - interval; 
				 
				  	var leave1 = this.nTime;//计算天数后剩余的毫秒数
				 	var t = Math.floor(Math.floor((leave1/(3600*1000))/24));
				  	var hleave = this.nTime%((24*3600*1000));
				  	//把剩余毫秒数转换为小时
					var h = Math.floor(hleave/(3600*1000)) < 10 ? "0"+ Math.floor(hleave/(3600*1000)) : Math.floor(hleave/(3600*1000));	
					var leave2 = this.nTime%(3600*1000);        //计算小时数后剩余的毫秒数
					//把转换小时之后，剩余毫秒数转换为分钟
					var m = Math.floor(leave2/(60*1000)) < 10 ? "0" + Math.floor(leave2/(60*1000)) : Math.floor(leave2/(60*1000));
					
					//把转换分钟之后，剩余毫秒数转换为秒
					var leave3 = leave2%(60*1000);      //计算分钟数后剩余的毫秒数