先看代码：

Ext.extend(demo.module, {
    init: function(){
        var myData = [
            ['3m Co',71.72,0.02,0.03,'9/1 12:00am'],
            ['Alcoa Inc',29.01,0.42,1.47,'9/1 12:00am'],
            ['Altria Group Inc',83.81,0.28,0.34,'9/1 12:00am'],
            ['American Express Company',52.55,0.01,0.02,'9/1 12:00am'],
            ['American International Group, Inc.',64.13,0.31,0.49,'9/1 12:00am'],
            ['AT&T Inc.',31.61,-0.48,-1.54,'9/1 12:00am'],
            ['Boeing Co.',75.43,0.53,0.71,'9/1 12:00am'],
            ['Caterpillar Inc.',67.27,0.92,1.39,'9/1 12:00am'],
            ['Citigroup, Inc.',49.37,0.02,0.04,'9/1 12:00am'],
            ['E.I. du Pont de Nemours and Company',40.48,0.51,1.28,'9/1 12:00am'],
            ['Exxon Mobil Corp',68.1,-0.43,-0.64,'9/1 12:00am'],
            ['General Electric Company',34.14,-0.08,-0.23,'9/1 12:00am'],
            ['General Motors Corporation',30.27,1.09,3.74,'9/1 12:00am'],
            ['Hewlett-Packard Co.',36.53,-0.03,-0.08,'9/1 12:00am'],
            ['Honeywell Intl Inc',38.77,0.05,0.13,'9/1 12:00am'],
            ['Intel Corporation',19.88,0.31,1.58,'9/1 12:00am'],
            ['International Business Machines',81.41,0.44,0.54,'9/1 12:00am'],
            ['Johnson & Johnson',64.72,0.06,0.09,'9/1 12:00am'],
            ['JP Morgan & Chase & Co',45.73,0.07,0.15,'9/1 12:00am'],
            ['McDonald\'s Corporation',36.76,0.86,2.40,'9/1 12:00am'],
            ['Merck & Co., Inc.',40.96,0.41,1.01,'9/1 12:00am'],
            ['Microsoft Corporation',25.84,0.14,0.54,'9/1 12:00am'],
            ['Pfizer Inc',27.96,0.4,1.45,'9/1 12:00am'],
            ['The Coca-Cola Company',45.07,0.26,0.58,'9/1 12:00am'],
            ['The Home Depot, Inc.',34.64,0.35,1.02,'9/1 12:00am'],
            ['The Procter & Gamble Company',61.91,0.01,0.02,'9/1 12:00am'],
            ['United Technologies Corporation',63.26,0.55,0.88,'9/1 12:00am'],
            ['Verizon Communications',35.57,0.39,1.11,'9/1 12:00am'],
            ['Wal-Mart Stores, Inc.',45.45,0.73,1.63,'9/1 12:00am']
        ];
        
        var store = new Ext.data.SimpleStore({
            fields: [
               {name: 'company'},
               {name: 'price', type: 'float'},
               {name: 'change', type: 'float'},
               {name: 'pctChange', type: 'float'},
               {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
            ]
        });
        store.loadData(myData);
        var grid = new Ext.grid.GridPanel({
            store: store,
            columns: [
                {id:'company',header: "Company", width: 160, sortable: true, dataIndex: 'company'},
                {header: "Price", width: 75, sortable: true, renderer: 'usMoney', dataIndex: 'price'},
                {header: "Change", width: 75, sortable: true, renderer: this.change, dataIndex: 'change'},
                {header: "% Change", width: 75, sortable: true, renderer: this.pctChange, dataIndex: 'pctChange'},
                {header: "Last Updated", width: 85, sortable: true, renderer: Ext.util.Format.dateRenderer('m/d/Y'), dataIndex: 'lastChange'}
            ],
            stripeRows: true,
            autoExpandColumn: 'company',
            height:350,
            width:600,
            title:'Array Grid'
        });
        
        this.main.add(grid);
        this.main.doLayout();
    },
    change: function(val){
        if(val > 0){
            return '<span style="color:green;">' + val + '</span>';
        }else if(val < 0){
            return '<span style="color:red;">' + val + '</span>';
        }
        return val;
    },
    pctChange: function(val){
        if(val > 0){
            return '<span style="color:green;&q