document.observe('dom:loaded', function(){

	$$('.category_menu img').each(function(el){
		if(el.alt=='+' || el.alt=='-')
			el.observe('click', checkLI.bindAsEventListener(el));
	}, this);
});

function checkLI(event){

	var li = $(this).ancestors()[0];
	var url = this.src.substring(0,this.src.lastIndexOf('/')+1);
	var ext = this.src.substr(this.src.lastIndexOf('.'));
	var action;
	if(li.hasClassName('open')){
		li.removeClassName('open');
		li.addClassName('close');
		action = 'close';
		// zmenit obrazek
		this.alt = '+';
		this.src = url+'plus'+ext;
	}
	else {
		li.removeClassName('close');
		li.addClassName('open');
		action = 'open';
		// zmenit obrazek
		this.alt = '-';
		this.src = url+'minus'+ext;
	}

	new Ajax.Request(application_products_categories+'CATEGORY_MENU/' +action+'/'+li.id);
}