ssi filter js

gistfile1.js

var makeElm = function(type) {
    return document.createElement(type);
};

var frm = document.forms.filter,
    list_groups = document.getElementsByClassName('filter_groups')[0],
    list_suppliers = document.getElementsByClassName('filter_suppliers')[0],
    array_groups = [],
    array_suppliers = [];

function addToList(selected, arr, list, delCallback) {
    if (!selected.value || arr.indexOf(selected.value) !== -1) {
        return;
    }
    var item = makeElm('div'),
        del = makeElm('a');
    item.appendChild(document.createTextNode(selected.textContent));
    del.addEventListener('click', delCallback, false);
    del.appendChild(document.createTextNode("[X]"));
    del.id = selected.value;
    item.appendChild(del);
    list.appendChild(item);
    arr.push(selected.value);
}

function removeFromList(obj, arr) {
    var match = obj.id;
    arr.splice(arr.indexOf(match), 1);
    var item = obj.parentNode;
    item.parentNode.removeChild(item);
}

var addGroupToList = function() {
    addToList(this[this.selectedIndex], array_groups, list_groups, function() {
        removeFromList(this, array_groups);
    });
    this[0].selected = true;
};
var addSupplierToList = function() {
    addToList(this[this.selectedIndex], array_suppliers, list_suppliers, function() {
        removeFromList(this, array_suppliers);
    });
    this[0].selected = true;
};


frm.groups.addEventListener('change', addGroupToList, false);
frm.suppliers.addEventListener('change', addSupplierToList, false);