function darkBack(id) {
	document.getElementById (id).className = "katalog_item_dark";
}
function lightBack(id) {
	document.getElementById (id).className = "katalog_item";
}
function darkBackRight(id) {
	document.getElementById (id).className = "katalog_item_right_dark";
}
function lightBackRight(id) {
	document.getElementById (id).className = "katalog_item_right";
}