当Grid中没有数据的时候,如何用F.js提示

 <ext:Button ID = "Submit96" Text="提交至报告审核" runat="server" OnClientClick="Submit96_Click();return 0;" Hidden="true" ValidateForms="Form9"/> 

function Submit96_Click() {
var grid = F('<%= Grid3.ClientID %>');
var store = grid.getStore();
var count = store.getCount();


if (count == 0) {
F.util.alert("未上传原始记录不能提交审核！");
return 0;
}
F('<%= Window7.ClientID %>').f_show();
}