function changeCategory(who) {
	sc = who.form.elements["subcategory_id"];
	sc.options.length = 1;
	
	if(who.selectedIndex > 0) {
		cat = who.options[who.selectedIndex].value;
		if(subCat[cat]) {
			for(i = 0 ; i < subCat[cat].length ; i++) {
        sc.options[(i+1)] = new Option(subCat[cat][i][1], subCat[cat][i][0], false, false);
			}
		}
	}
}

var maxOrder = false;
function orderAdd(elem, m) {
    maxOrder = m;
    $$('.amountpopup').each(function(s) {
        s.parentNode.style.position = 'static';
        s.remove();
    });

    var originalUrl = elem.href;

    var popup =  Builder.node('div', { className: 'amountpopup' });
    var label =  Builder.node('label', [Builder.node('strong', 'Aantal')]);
    var input =  Builder.node('input', { type: 'text', name: 'amount', value: '1', size: '2', maxLength: '2' });
    var submit = Builder.node('input', { type: 'submit', value: 'Toevoegen' });
    var submit2 = Builder.node('input', { type: 'submit', value: 'sluiten' });
    
    popup.appendChild(label);
    popup.appendChild(input);
    popup.appendChild(submit);
    popup.appendChild(submit2);

    submit.onclick = function() {
        if(input.value > maxOrder) {
        	alert("Er zijn er dart nog maar " + maxOrder + " op voorraad. Dus je kan er geen " + input.value + " bestellen");
        } else {
        	if(input.value > 0) {
            	window.location = originalUrl + '&amount=' + input.value;
        	} else {
	            $(popup).remove();
    	    }
    	}
    };
	submit2.onclick = function() {
		$(popup).remove();
	};

    elem.parentNode.style.position = 'relative';
    elem.parentNode.appendChild(popup);

    return false;
}