using iframe to manage upload of schemas - allows for calling an action listener once the upload is complete to validate the schema and present an error message inside the form in a pretty way.

added a small helper library for managing uploads without using a page reload.  modified uploadfileservlet to return a javascript snippet in the response body if the return-page parameter starts with javascript:

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@4578 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/web/scripts/upload_helper.js

@@ -0,0 +1,50 @@
+var _uploads = [];
+
+function handle_upload_helper(fileInputElement,
+                              uploadId,
+                              callback,
+                              contextPath)
+{
+  var id = fileInputElement.getAttribute("name");
+  var d = fileInputElement.ownerDocument;
+  var iframe = d.createElement("iframe");
+  iframe.style.display = "none";
+  iframe.name = id + "upload_frame";
+  iframe.id = iframe.name;
+  document.body.appendChild(iframe);
+
+  // makes it possible to target the frame properly in ie.
+  window.frames[iframe.name].name = iframe.name;
+
+  _uploads[uploadId] = { path: fileInputElement.value, callback: callback };
+
+  var form = d.createElement("form");
+  d.body.appendChild(form);
+  form.style.display = "none";
+  form.method = "post";
+  form.encoding = "multipart/form-data";
+  form.enctype = "multipart/form-data";
+  form.target = iframe.name;
+  form.action = contextPath + "/uploadFileServlet";
+  form.appendChild(fileInputElement.cloneNode(true));
+
+  var id = document.createElement("input");
+  form.appendChild(id);
+  id.type = "hidden";
+  id.name = "upload-id";
+  id.value = uploadId;
+
+  var rp = document.createElement("input");
+  form.appendChild(rp);
+  rp.type = "hidden";
+  rp.name = "return-page";
+  rp.value = "javascript:window.parent.upload_complete_helper('" + uploadId + "')";
+
+  form.submit();
+}
+
+function upload_complete_helper(id)
+{
+  var upload = _uploads[id];
+  upload.callback(id, upload.path);
+}