function isnum(putativenumber,name,sign,zero,integer) //enter the variable to be checked,
//the name of the variable ('off', if you want no message displayed), and if desired, "plus" if it must be positive,  "no" if it can't be zero, and "yes" if it must be an integer.
{
	var checkOK = "-0123456789.,";
	var checkStr = putativenumber;
	var allValid = true;
	var decPoints = 0;
	var allNum = "";
	var commas= false;
	for (i = 0; i < checkStr.length; i++)
		{
		ch = checkStr.charAt(i);
		for (j = 0; j <= checkOK.length; j++)
			{		
				if (ch == checkOK.charAt(j))
					break;
				if (j == checkOK.length)
					{
					allValid = false;
					}
			}
		if (ch == ".")
			{
			decPoints++;
			}
 		if (ch == ",")
			{
			commas= true;
			}
		}
	if (!allValid && checkStr!=" ")
		{
		if (name!="off")
			{
			alert("Please enter only numbers for "+name+".");
			}
		return (false);
		}
		else if (commas)
			{
			alert("Please do not include any commas in "+name+".");
			return (false);
			}
			else if (decPoints > 1 )
				{
				if (name!="off")
					{
					alert("Please enter only numbers for "+name+".");
					}
				return (false);
				}
				else if ((putativenumber < 0) && (sign=="plus"))
					{
					if (name!="off")
						{
						alert("Please enter only positive numbers for "+name+".");
						}
					return(false);
					}
						else if ((putativenumber ==0) && (zero=="no"))
						{
						if (name!="off")
							{
							alert("Please enter non-zero numbers for "+name+".");
							}
						return(false);
						}
							else if ((Math.floor(putativenumber)!=putativenumber) && (integer=="yes"))
							{
							if (name!="off")
								{
								alert("Please enter only integers for "+name+".");
								}
							return(false);
							}
								else 
								{
								return (true);
								}

}

function check(TheField)
{
	if (isnum(TheField,"off")&& TheField !="" && TheField!=" "){
		return (true);
		}
	else {
		return (false);
	}	
}

function getselectedbutton(buttongroup)
	{
	 for (var i=0; i <buttongroup.length;i++)
		{
		if (buttongroup[i].checked)
			{
			return buttongroup[i].value;
			break;
			}
		}
	alert("you must select a value from the radio buttons");
	return(false);
	}