js计算时间差

//计算时间差
    function GetDateDiff(startTime, endTime, diffType) {
        //将xxxx-xx-xx的时间格式，转换为 xxxx/xx/xx的格式
        startTime = startTime.replace(/\-/g, "/");
        endTime = endTime.replace(/\-/g, "/");
        //将计算间隔类性字符转换为小写   
        diffType = diffType.toLowerCase();
        var sTime = new Date(startTime);      //开始时间
        var eTime = new Date(endTime);  //结束时间  
        //作为除数的数字
        var divNum = 1;
        switch (diffType) {
            case "second":
                divNum = 1000;
                break;
            case "minute":
                divNum = 1000 * 60;
                break;
            case "hour":
                divNum = 1000 * 60 * 60;
                break;
            case "day":
                divNum = 1000 * 60 * 60 * 24;
                break;
            default:
                break;
        }
        return parseInt((eTime.getTime() - sTime.getTime()) / parseInt(divNum));