function checkIt(obj) {
	var chk = MM_findObj(obj);
	chk.checked=!(chk.checked);
}
function change_images() {
	var categoryids = new Array(1,2,3,6,7)
	var none = true;
	for (var i = 0;i < categoryids.length;i++) {
		chk = MM_findObj('category_'+categoryids[i])
		if (chk.checked) {
			MM_swapImage('img_cat'+categoryids[i],'','images/category_'+categoryids[i]+'.gif',0)
			none = false
		}
		else
			MM_swapImage('img_cat'+categoryids[i],'','images/category_'+categoryids[i]+'_o.gif',0)
	}
	if (none) {
		for (var i = 0;i < categoryids.length;i++) {
			MM_swapImage('img_cat'+categoryids[i],'','images/category_'+categoryids[i]+'.gif',0)
		}
	}
}
onLoad(function() {MM_preloadImages('images/category_1.gif','images/category_2.gif','images/category_3.gif','images/category_6.gif','images/category_7.gif')})
onLoad(change_images)