window.onload = function()
{
	var selectCntrl = document.searchFrm.listingtype;
	var selIndx = selectCntrl.selectedIndex;
	var opt = selectCntrl.options[selIndx];
		
	if (selIndx != 0)
	{
		filterSearch(opt);
	}
}


function OptionControl(value, display)
{
	this.value = value;
	this.display = display;
}

function clearOptions(selectCntrl)
{
	while (selectCntrl.options.length > 0)
	{
		if (selectCntrl.options.remove)
			selectCntrl.options.remove(0);
		else
			selectCntrl.options[0] = null;
	}
}

function addOptionControl(selectCntrl, optionCntrl, bSelect)
{
	var opt = new Option();
	var pos = selectCntrl.options.length;
	opt.value = optionCntrl.value;
	selectCntrl.options[selectCntrl.options.length] = opt;
	selectCntrl.options[pos].text = optionCntrl.display;
	selectCntrl.options[pos].selected = bSelect;
}

function filterSearch(opt)
{
	var index = opt.value;
	var slctCategories = document.searchFrm.category;
	clearOptions(slctCategories);

	addOptionControl(slctCategories, new OptionControl(0, "All"), true);

	if (index == 0)
	{
		for (var i=1; i < listings.length; i++)
		{
			for (var j=0; j < listings[i].length; j++)
			{
				var currentOption = listings[i][j];
				addOptionControl(slctCategories, currentOption);
			}
		}
	}
	else
	{
		for (var i=0; i < listings[index].length; i++)
		{
			var currentOption = listings[index][i];
			addOptionControl(slctCategories, currentOption);
		}
	}
}