static/ext/src/ux/grid/filter/StringFilter.js
function (record) {
        var val = record.get(this.dataIndex);

        if(typeof val != 'string') {
            return (this.getValue().length === 0);
        }

        return val.toLowerCase().indexOf(this.getValue().toLowerCase()) > -1;
    }
function (record) {
        var val = record.get(this.dataIndex);

        if(typeof val != 'string') {
            return (this.getValue().length === 0);
        }

        return val.toLowerCase().indexOf(this.getValue().toLowerCase()) > -1;
    }
Template method that is to validate the provided Ext.data.Record
against the filters configuration.
@param {Ext.data.Record} record The record to validate
@return {Boolean} true if the record is valid within the bounds
of the filter, false otherwise.