function isNum(passedVal)
	{
		if(passedVal == "")
		{
			return false;
		}
	
		if(passedVal < "0") 
		{
			return false;
		}
		
		if(passedVal > "9")
		{
			return false;
		}
		
		return true;
	}


	function dateMask(theField)
	{	
		fieldContent = theField.value;
		
		var stringMask = "MM/DD/YYYY";
		var newString = "";
		var newStringIndex = 0;
		var themonth = "";
		var theday = "";
		var theyear = "";
		var dayindex = 2;
		var yearindex = 2;
		
		if(fieldContent != stringMask && fieldContent.length)
		{
			if(isNum(fieldContent.charAt(0)) && !isNum(fieldContent.charAt(1)))
			{				
				themonth = "0" + fieldContent.charAt(0);
				dayindex = 2;
			}
			else
			{
				themonth = fieldContent.charAt(0) + fieldContent.charAt(1); 
				dayindex = 3;
			}
			
			
			if(isNum(fieldContent.charAt(dayindex)) && !isNum(fieldContent.charAt(dayindex+1)))
			{				
				theday = "0" + fieldContent.charAt(dayindex);
				yearindex = dayindex+2;
			}
			else
			{
				theday = fieldContent.charAt(dayindex) + fieldContent.charAt(dayindex+1); 
				yearindex = dayindex+3;
			}
			
			for(i = yearindex; i < fieldContent.length;i++)
			{
				theyear += fieldContent.charAt(i);
			}
			
			if(theyear.length == 4)
			{
				theyear = theyear.charAt(2) + theyear.charAt(3);	
			}		
			
			var testyear = new Number ("20" + theyear);
			var testmonth = new Number (themonth);
			var testday = new Number (theday);
			
			if((testyear >= 2000 && testyear <= 3000) && (testmonth >= 1 && testmonth <= 12) && (testday >= 1 && testday <= 31))
			{
				newString = themonth + "/" + theday + "/" + theyear;
				theField.value = newString;
			}
			else
			{
				theField.value = '';	
				theField.focus();
				alert("That is not a valid date mm/dd/yyyy, please try again.");
				return(0);
			}			
  		}
  		else
  		{
  			theField.value = '';
  		}
	}