function err(t) { alert('Error ' + t.status + ' -- ' + t.statusText); }

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

	switch(true)
	{
		case !!$('sfrm'):
			$('sfrm_cat').observe('change',function() {
				if(this.value != '-1')
				{
			        new Ajax.Request(application_root + 'xhr/add/'+this.value, {
	        	    	method: 'get',
		            	onComplete: fill_subcat,
	            		onFailure: err
		        	});
				}
			});
			$('sfrm_scat').observe('change',function()
			{
				fill_sscat(this.value);
			});
		break;
	}
});

function fill_subcat(resp)
{
	var scat = $('sfrm_scat');
	scat.innerHTML = resp.responseText;
	fill_sscat(scat.value);
}

function fill_sscat(id)
{
    if(id == '-1') $('sfrm_sscat').innerHTML = '<option value="-1">nezáleží</option>';
    else
    {
        new Ajax.Request(application_root + 'xhr/add/' + id, {
            method: 'get',
            onComplete: function(resp){
                $('sfrm_sscat').innerHTML = resp.responseText;
            },
            onFailure: err
        });
    }
}