<!-- 相差天数-->

	function datedifference(startDate, endDate) {

	        var dateSpan,

	            tempDate,

	            iDays;

	        sDate1 = Date.parse(startDate);

	        sDate2 = Date.parse(endDate);

	        dateSpan = sDate2 - sDate1;

	        dateSpan = Math.abs(dateSpan);

	        iDays = Math.floor(dateSpan / (24 * 3600 * 1000));

	        return iDays

　　　　};

	    <!-- 相差月数或者年数-->

      function monthdifference(startDate, endDate) {

    	  let a = new Date(startDate);

          let b = new Date(endDate);

          //年

          let year = b.getFullYear()	-	a.getFullYear();

          //月

          let month = b.getMonth()	-	a.getMonth()+1;

	  return month

　　　};