日期相减得到小时数

//返回小时数

function diffDate(orderStartTime){

var nowDate = new Date();

var startTime = new Date(orderStartTime);

var s1 = nowDate.getTime()

var s2 = startTime.getTime();

var total = (s2 - s1)/1000;

var day = parseInt(total / (24*60*60));//计算整数天数

var afterDay = total - day*24*60*60;//取得算出天数后剩余的秒数

var hour = parseInt(afterDay/(60*60));//计算整数小时数

return hour;

}