function isDate(DateString)
{
  var tempy='';  //year
  var tempm='';  //month
  var tempd='';  //date
  var tempArray; //store the date
  if(DateString.length<8 && DateString.length>10)
  {
    alert("日期长度为8-10位！");
    return false;
  }
  tempArray = DateString.split('-');  //split the datestring by '-'
  if (tempArray.length!=3)
  {
     alert("日期格式不对！正确的应为(年-月-日)"); //wrong date format
     return false;
  }
  if (tempArray[0].length==4)
  {
     tempy = tempArray[0];
     tempm = tempArray[1];
     tempd = tempArray[2];
  }
  else
  {
    alert("日期格式不对！正确的应为(年-月-日)");
    return false;
  }
  var tDateString = tempy + '/'+tempm + '/'+tempd+' 8:0:0';
  var tempDate = new Date(tDateString);
  if (isNaN(tempDate))  return false;
  if (((tempDate.getUTCFullYear()).toString()==tempy) && (tempDate.getMonth()==eval(tempm+'-1')) && (tempDate.getDate()==eval(tempd)))
     return true;
  else
  {
    alert("无效的日期输入！");
    return false;
  }
}

function isInteger(string,sign)
{
 var integer;
 if((sign!=null) && (sign!='-') && (sign!='+')) return false;
 integer = parseInt(string);
 if(isNaN(integer)) return false;
 else
 if(integer.toString().length==string.length)
 {
    if ((sign==null) || (sign=='-' && integer<0) || (sign=='+' && integer>0))
     return true;
    else return false;
 }
 else
 return false;
}

//只能输入4-20个以字母开头、可带数字、“_”、“.”的字串
function isUsername(s)
{
  var patrn=/^[a-zA-Z]{1}([a-zA-Z0-9]|[._]){3,19}$/;
  if (!patrn.exec(s))  return false;
  return true;
}

//密码只能4-20字母、数字、下划线
function isPassword(s)
{
 var patrn=/^(\w){4,20}$/;
 if (!patrn.exec(s)) return false;
 return true;
}

//check if it is telephone number
function isTelnum(s)
{
 var patrn=/^[+]{0,1}(\d){1,3}[ ]?([-]?((\d)|[ ]){1,12})+$/;
 if (!patrn.exec(s)) return false;
 return true;
}

//check if it is digit
function isDigit(s)
{
  var patrn=/^[0-9]{1,20}$/;
  if (!patrn.exec(s)) return false;
  return true;
}

//chek valid email
function isEmail (theStr)
{
  var atIndex = theStr.indexOf('@');
  var dotIndex = theStr.indexOf('.', atIndex);
  var flag = true;
  theSub = theStr.substring(0, dotIndex+1)

  if ((atIndex < 1)||(atIndex != theStr.lastIndexOf('@'))||(dotIndex < atIndex + 2)||(theStr.length <= theSub.length))
  { return(false); }
  else { return(true); }
}

<script language="JavaScript" type="text/JavaScript">
<!--
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}

function MM_preloadImages() { //v3.0
  var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
    var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
    if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}

function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_swapImage() { //v3.0
  var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
   if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}

function checkrequired(which) {
var pass=true;
if (document.images) {
for (i=0;i<which.length;i++) {
var tempobj=which.elements[i];
if (tempobj.name.substring(0,8)=="required") {
if (((tempobj.type=="text"||tempobj.type=="textarea")&&
tempobj.value=='')||(tempobj.type.toString().charAt(0)=="s"&&
tempobj.selectedIndex==0)) {
pass=false;
break;
         }
      }
   }
}
if (!pass) {
shortFieldName=tempobj.name.substring(8,30).toUpperCase();
alert("叫絋粄 "+shortFieldName+" 逆タ絋恶");
return false;
}
else
return true;
}


//-->
</script>