function convert()
{
	var unit = document.convertMM.unit.value
	var value = document.convertMM.value.value
	valueNum = parseFloat(value)
	if(!value)
	{
		alert("Please enter a value to convert")
	}
	else
	{
		if(unit == "cm")
		{
			var mm = value * 10
			alert(valueNum + "cm = " + mm + "mm")
		}
		if(unit == "inch")
		{
			var mm = value * 25.4
			alert(valueNum + '" = ' + mm + "mm")
		}
		if(unit =="0")
		{
			alert("Please select a unit to convert from")
		}
	}
}