how to download a file from geoserver gml from a url using javascript?

how to download a file from geoserver gml from a url using javascript?

I'm doing a web application with javascript, but I could not download files from geoserver, the url given entry does not bring any result.

enter the url using this instruction:

new Ext.form.TextField({

                disabled: false,
                        fieldLabel: "URL GML",
                        value:'',
            id:"Ugml"

to save a link:

var Ugml = Ext.getCmp('Ugml').getValue()

to fetch the data:

xmlhttp = new XMLHttpRequest();

xmlhttp.open("GET", Ext.getCmp('Ugml').getValue(),true, User="admin",Password="geoserver");
         xmlhttp.send(null);
         alert(xmlhttp.responseXML.xml);

any ideas

Thanks for your answers

Answer

I would really need to see your URL to comment on why it doesn't work. Have you tried something like http://ian01.geog.psu.edu:80/geoserver/wfs?request=GetFeature&version=1.1.0&typeName=topp:states&outputFormat=GML2

In general though WFS requests are made using POST (not GET) with an XML payload to handle the request as it is easy to run into URL length limits before the request gets too complex.

Finally I'd recommend using OpenLayers and GeoEXT to provide this functionality with well tested code that saves you the work of developing and testing.