Maybe i did not describle exactly. we just want use the function as the attch file. 

The picture just change webgrid's column,but use the JavaScript(WebGrid1.RefreshAll()), the webgrid will structure again,so the unsaved data will lost.

When you modify data on the webgrid,reset the columns' visible,use the following JavaScript ,data will lost.

<script language="javascript" type="text/javascript">

    <!--

    function button1_onclick() {

        var WebGrid1 = ISGetObject("WebGrid1");

        var rootTable = WebGrid1.GetRootTable();

        var PhoneColumn = rootTable.Columns.GetNamedItem("Phone");

        PhoneColumn.Set("Visible", "false", true);

        WebGrid1.RefreshAll();

        return true;

    }

    // -->

</script>