add javascript form validation to materials upload form

- Legacy-Id: 5919

ietf/secr/templates/proceedings/upload_unified.html

@@ -83,7 +83,7 @@
      
      <div class="inline-related">
        <h2>Upload Materials</h2>
-       <form enctype="multipart/form-data" action="." method="post">
+       <form id="upload_materials_form" enctype="multipart/form-data" action="." method="post">
        <table class="center" id="proceedings-upload-table">
        {{ form.as_table }}
        </table>

static/secr-static/js/utils.js

@@ -211,4 +211,15 @@ $(document).ready(function() {
       init_proceedings_upload();
   }
 
+  // validate form upload form before uploading file
+  if ($('#upload_materials_form').length) {
+    $('#upload_materials_form').submit(function() {
+        var x=$('#id_slide_name').val();
+        if (x==null || x=="")
+        {
+            $('#id_slide_name').before('<ul class="errorlist"><li>This field is required.</li></ul>');
+            return false;
+        }
+    });
+  }   
 });