function setTag(tag, inputId)
{
	value = document.getElementById(inputId).value;
	units = value.split(" ");
	newvalue = "";
	var exists = false;
	for (i=0;i<units.length;i++)
	{
		if (units[i] != "")
		{
			if (units[i] == tag)
			{
				exists = true;
			}
			else
			{
				newvalue += units[i] + " ";
			}
		}
	}
	if (!exists)
	{
		newvalue += tag;
	}
	document.getElementById(inputId).value = newvalue;
}