function doCat(currCat)
{
	SignId = "sign" + currCat;
	CatId = "cat" + currCat;
	currSign = document[SignId].src;
	currSign = currSign.substr(currSign.lastIndexOf("/")+1, 3);

	if (currSign=="min")
	{
		document[SignId].src = "images/plus.jpg";
		document.getElementById(CatId).style.display = 'none';
	}
	else
	{
		document[SignId].src = "images/minus.jpg";
		document.getElementById(CatId).style.display = 'block';	
	}
	document[SignId].blur();
}

function catSelect()
{
	document.getElementById("articles").submit();
}