javascript验证函数

/**
 * DHTML date validation script.
 */
// Declaring valid date character, minimum year and maximum year
var dtCh= "-";
var minYear=1900;
var maxYear=2100;
function isInteger(s){
 var i;
    for (i = 0; i < s.length; i++){  
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}
function stripCharsInBag(s, bag){
 var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){  
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}
function daysInFebruary (year){
 // February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) {
 for (var i = 1; i <= n; i++) {
  this[i] = 31
  if (i==4 || i==6 || i==9 || i==11) {this[i] = 30}
  if (i==2) {this[i] = 29}
   }
   return this
}
function isDate(dtStr){
 var daysInMonth = DaysArray(12)
 var pos1=dtStr.indexOf(dtCh)
 var pos2=dtStr.indexOf(dtCh,pos1+1)
 var strYear=dtStr.substring(0,pos1)
 var strMonth=dtStr.substring(pos1+1,pos2)
 var strDay=dtStr.substring(pos2+1)
 strYr=strYear
 
 var temStrDay="";
 var temStrMonth="";
 //alert( strMonth.length );
 if (strDay.charAt(0)=="0" && strDay.length>1) temStrDay=strDay.substring(1)
 if (strMonth.charAt(0)=="0" && strMonth.length>1) temStrMonth=strMonth.substring(1)
 
 for (var i = 1; i <= 3; i++) {
  if (strYr.charAt(0)=="0" && strYr.length>1) strYr=strYr.substring(1)
 }
 month=parseInt(temStrMonth)
 day=parseInt(temStrDay)
 year=parseInt(strYr)
 if (pos1==-1 || pos2==-1){
   controlSubmit =false;
  alert("时间格式为:2006－09－03")
 return ;
 }
 if (strMonth.length != 2 || month<1 || month>12){
  controlSubmit =false;
  alert("请输入合法的月,例如:02")
 return ;
 }
 if (strDay.length != 2 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
   controlSubmit =false;
   alert("请输入合法的日,例如:02")
   return ;
 }
 if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
 controlSubmit =false;
  alert("请输入 4 位数的年份在  "+minYear+" 和 "+maxYear+"之间")
 return ;
 }
 if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
   controlSubmit =false;
  alert("请输入合法的时间格式例如:2006－09－03")
  return ;
 }
controlSubmit =true;
}