Filtering an n-columned ExtJS grid from a searchbox

omnisearch.js

onSearchFieldChange: function (obj, value) {
    var store, searchRegExp;

    store = Ext.getStore();
    store.clearFilter();
    searchRegExp = new RegExp(value, 'i');

    store.filterBy(function (item) {
        var i = 0,
            l = Object.keys(item.data).length;

        for (; i < l; i++) {
            if (searchRegExp.test(item.get(Object.keys(item.data)[i]))) {
                return true;
            }
        }
    });
}