function collapse_menu(item_id) {
	var item_id;
	var item = document.getElementById('item'+item_id);
	var submenu = document.getElementById('submenu'+item_id);
	if (submenu.style.display != 'block') {
		item.className = 'active';
		submenu.style.display = 'block';
	} else {
		item.className = 'unactive';
		submenu.style.display = 'none';
	}
}

function collapse(id) {
	var form = document.getElementById(id);
	if (form.style.display != 'block') {
		form.style.display = 'block';
	} else {
		form.style.display = 'none';
	}
}


function collapse_popup(block) {
	var block = document.getElementById(block);
	var feedback = document.getElementById('feedback');
	var scrollTop = document.documentElement.scrollTop;
	var windowHeight = document.documentElement.clientHeight;
	if (block.style.display != 'block') {
		feedback.style.display = 'none';
		block.style.display = 'block';
		block.style.top = scrollTop + windowHeight/2 - block.offsetHeight/2 + 'px';
	} else {
		block.style.display = 'none';
	}
}