JQGRID is not invoking the ASPX Page function

Somehow the JQGrid is not invoking the aspx page function at all. I dont know what I am doing wrong. this is the first time, I am trying to use the combination of XML & aspx. I dont want to use the ASHX & JSON.

<script src="jqgrid/jquery-1.10.2.js" type="text/javascript"></script>
<script src="jqgrid/jquery-ui-1.10.4.custom.js" type="text/javascript"></script>
<script src="jqgrid/jquery-ui-1.10.4.custom.min.js" type="text/javascript"></script>
<script src="jqgrid/jquery.jqGrid.js" type="text/javascript"></script>
<script src="jqgrid/grid.locale-en.js" type="text/javascript"></script>


<asp:Content ID="Content1" ContentPlaceHolderID="headContent" runat="Server">
    <script type="text/javascript">

        $(document).ready(function () {
            $("#list").jqGrid({                 
                url: "http://XMLCheck.aspx/getData",
                datatype:  'xmlstring',
                ajaxGridOptions: { contentType: 'application/xml; charset=utf-8' },
                mtype: 'POST',
                colNames: ['Inv No', 'Date', 'Amount', 'Tax', 'Total', 'Notes'],
                colModel: [
                  { name: 'invid', index: 'invid', width: 55, sorttype: 'int' },
                  { name: 'invdate', index: 'invdate', width: 90, sorttype: 'date', datefmt: 'Y-m-d' },
                  { name: 'amount', index: 'amount', width: 80, align: 'right', sorttype: 'float' },
                  { name: 'tax', index: 'tax', width: 80, align: 'right', sorttype: 'float' },
                  { name: 'total', index: 'total', width: 80, align: 'right', sorttype: 'float' },
                  { name: 'note', index: 'note', width: 150, sortable: false }],
                pager: '#pager',
                rowNum: 10,
                viewrecords: true                
            });
        });

</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="Server">
   <table id="list"></table>
    <div id="pager"></div>
</asp:Content>

aspx page has

<WebMethod> _
Public Shared Function getData() As String

        Return "<?xml version='1.0' encoding='utf-8'?><invoices><rows><row><cell>data1</cell><cell>data2</cell><cell>data3</cell><cell>data4</cell><cell>data5</cell><cell>data6</cell></row></rows></invoices>"


End Function