比较日期 结束日期不能早于开始日期

01.function getUserWorkId(CreateTime,SolveTime)     02.{       03.        04.       var DateOne = document.getElementById(CreateTime).value;     05.       var DateTwo = document.getElementById(SolveTime).value;      06.    07.       var OneMonth = DateOne.substring(5,DateOne.lastIndexOf ('-'));            08.       var OneDay = DateOne.substring(DateOne.length,DateOne.lastIndexOf ('-')+1);            09.       var OneYear = DateOne.substring(0,DateOne.indexOf ('-'));         10.        11.       var TwoMonth = DateTwo.substring(5,DateTwo.lastIndexOf ('-'));            12.       var TwoDay = DateTwo.substring(DateTwo.length,DateTwo.lastIndexOf ('-')+1);            13.       var TwoYear = DateTwo.substring(0,DateTwo.indexOf ('-'));            14.       var cha=((Date.parse(OneMonth+'/'+OneDay+'/'+OneYear)- Date.parse(TwoMonth+'/'+TwoDay+'/'+TwoYear))/86400000);      15. if(DateTwo.length>0)     16.       {     17.         if(cha>0)     18.         {     19.            alert('计划结束日期不能早于开始日期！');     20.            return false;     21.         }     22.       }      23.}