jsp跳转至servlet

[winklq]

function updateCustomer() {
var selectedRows = $("#dg").datagrid('getSelections');
if (selectedRows.length != 1) {
$.messager.alert("系统提示", "请选择一条要编辑的数据！");
return;
}
var row = selectedRows[0];
window.location.href = "customerUpdateServlet?FNumber="+row.FNumber;
}
为什么总是报404的错误呢？
"./customerUpdateServlet?FNumber="+row.FNumber;这个也试过了同样报错