// JavaScript Document 								
function IsNumeric(sText)
{
	var ValidChars = "0123456789";
	var IsNumber=true;
	var Char;

for (i = 0; i < sText.length && IsNumber == true; i++) 
{ 
	Char = sText.charAt(i); 
	if (ValidChars.indexOf(Char) == -1) 
	{
		IsNumber = false;
	}
	}
		return IsNumber; 
	}
function calcTick(tick)
	{
		var Cost;
		if(IsNumeric(tick) == false)
	{
		alert("Not a valid number.");
	}
		else
	{
	// Get groups of 3
Cost = Math.floor(tick / 3) * 25;
	// Get the remainder
Cost = Cost + ((tick % 3) * 10);
document.getElementById("cost").value = "$" + Cost + ".00";
	}
	}