sfHover = function() {
	var sfEls = document.getElementById("nav").getElementsByTagName("LI");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=" sfhover";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp(" sfhover\\b"), "");
		}
	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);


/*
 * Clears a singe period row in the table so the data
 */
function ClearPeriod(from, to, cost, index)
{
	document.getElementById(from).value = "";
	document.getElementById(to).value = "";
	document.getElementById(cost).value = "";
	document.getElementById("from_display["+index+"]").innerHTML = "From Date";
	document.getElementById("to_display["+index+"]").innerHTML = "To Date";
}