// Validates that an event's keyCode is a valid numeric key or a control key
function checkNumeric(evt)
{
	// Only IE has a global event object, other browsers pass it in as an argument
	var e = (window.event) ? window.event : evt;
	if (evt.keyCode == 8			// Backspace
		|| evt.keyCode == 9			// Tab
		|| evt.keyCode == 27		// Escape
		|| evt.keyCode == 35		// End
		|| evt.keyCode == 36		// Home
		|| evt.keyCode == 37		// Left arrow
		|| evt.keyCode == 39		// Right arrow
		|| evt.keyCode == 46		// Delete
		|| (evt.keyCode > 47 && evt.keyCode < 58)	// Digits 0 - 9 (top of keyboard)
		|| (evt.keyCode > 95 && evt.keyCode < 106))	// Digits 0 - 9 (numeric keypad)
	{
		// IE expects the returnValue to be set, other browsers just expect the function to return true or false.
		e.returnValue = true;
		return true;
	}
	else
	{
		// IE expects the returnValue to be set, other browsers just expect the function to return true or false.
		e.returnValue = false;
		return false;
	}
}