Control asp:xml tag by JS

Question

I need help. In my old web page html was written using HtmlTextWriter and xml and xsl tags embedded like that:

 

writer.WriteBeginTag("xml");
writer.WriteAttribute("id", "data");
writer.WriteAttribute("src", "/edit/source.aspx?objIntel=DataBase\\" + objIntel + "&filename=\\xmls\\" + number_appl + ".xml&un=" + username);
writer.Write(HtmlTextWriter.TagRightChar);
writer.WriteEndTag("xml");
writer.WriteLine();

writer.WriteBeginTag("xml");
writer.WriteAttribute("id", "style");
writer.WriteAttribute("src", "/edit/source.aspx?objIntel=" + objIntel + "&filename=b7b.xsl&un=" + username);
writer.Write(HtmlTextWriter.TagRightChar);
writer.WriteEndTag("xml");
writer.WriteLine();

 That "data" id was called by javascript like that:

if (data.XMLDocument.text=="")
{
    showResult.innerHTML = "Object is missing";
    f1.subbuton.disabled=true;
    return;
}
showResult.innerHTML = data.transformNode(style.XMLDocument);

Now I'm using xml tag in asp.net like that:

<asp:Xml ID="data" runat="server" Visible="false" DocumentSource="~/20170001.xml"></asp:Xml>

And using the same JS code. But it says: x800a1391 - JavaScript runtime error: 'data' is undefined. What is the way to control asp:xml by JS in this condition? Am I missing some concepts?