js判断生效时间不得大于失效时间的思路及代码

<script type="text/javascript"> function check(){ //开始时间比结束时间大的验证 var validtime = document.form1.validtime.value; var invalidtime = document.form1.invalidtime.value; var beginTimes=validtime.substring(0,10).split('-'); var endTimes=invalidtime.substring(0,10).split('-'); validtime=beginTimes[1]+'/'+beginTimes[2]+'/'+beginTimes[0]+'/'+ validtime.substring(10,19); invalidtime=endTimes[1]+'/'+endTimes[2]+'/'+endTimes[0]+'/'+invalidtime.substring(10,19); var a =(Date.parse(invalidtime)-Date.parse(validtime))/3600/1000; if(a<0){ alert("失效时间不能小于生效时间!"); return; } var emergency = document.form1.emergency.value; if(emergency==""||regnull.test(emergency)){ alert("请输紧急程度!"); document.form1.emergency.focus(); return; } document.form1.submit(); } <script>