diff --git a/judge/forms.py b/judge/forms.py
index 057b86c..44acd0f 100644
--- a/judge/forms.py
+++ b/judge/forms.py
@@ -2,6 +2,8 @@ import os
 import secrets
 from operator import attrgetter
 import pyotp
+import time
+import datetime
 
 from django import forms
 from django.conf import settings
@@ -148,26 +150,33 @@ class ProblemSubmitForm(ModelForm):
             )
             self.fields["judge"].choices = judge_choices
 
+    def allow_url_as_source(self):
+        key = self.cleaned_data["language"].key
+        filename = self.files["source_file"].name
+        if key == "OUTPUT" and self.problem.data_files.output_only:
+            return filename.endswith(".zip")
+        if key == "SCAT":
+            return filename.endswith(".sb3")
+        return False
+
     def clean(self):
         if "source_file" in self.files:
-            if (
-                self.cleaned_data["language"].key in ["OUTPUT", "SCAT"]
-                and self.problem.data_files.output_only
-            ):
+            if self.allow_url_as_source():
                 filename = self.files["source_file"].name
-                if filename.endswith(".zip") or filename.endswith(".sb3"):
-                    self.source_file_name = (
-                        secrets.token_hex(16) + "." + filename.split(".")[-1]
-                    )
-                    filepath = os.path.join(
-                        settings.DMOJ_SUBMISSION_ROOT, self.source_file_name
-                    )
-                    with open(filepath, "wb+") as destination:
-                        for chunk in self.files["source_file"].chunks():
-                            destination.write(chunk)
-                    self.cleaned_data["source"] = self.request.build_absolute_uri(
-                        reverse("submission_source_file", args=(self.source_file_name,))
-                    )
+                now = datetime.datetime.now()
+                timestamp = str(int(time.mktime(now.timetuple())))
+                self.source_file_name = (
+                    timestamp + secrets.token_hex(5) + "." + filename.split(".")[-1]
+                )
+                filepath = os.path.join(
+                    settings.DMOJ_SUBMISSION_ROOT, self.source_file_name
+                )
+                with open(filepath, "wb+") as destination:
+                    for chunk in self.files["source_file"].chunks():
+                        destination.write(chunk)
+                self.cleaned_data["source"] = self.request.build_absolute_uri(
+                    reverse("submission_source_file", args=(self.source_file_name,))
+                )
             del self.files["source_file"]
         return self.cleaned_data
 
diff --git a/templates/problem/submit.html b/templates/problem/submit.html
index 178f2ac..1fc608c 100644
--- a/templates/problem/submit.html
+++ b/templates/problem/submit.html
@@ -2,7 +2,6 @@
 
 {% block js_media %}
   <script type="text/javascript" src="{{ ACE_URL }}/ace.js"></script>
-  <script type="text/javascript" src="{{ static('jszip/jszip.min.js') }}"></script>
   {{ form.media.js }}
   {% compress js %}
     <script type="text/javascript">
@@ -139,29 +138,15 @@
           }
         }
 
-        function get_source_scratch(file) {
-          JSZip.loadAsync(file).then(function($content) {
-            return $content.files["project.json"].async('text');
-          }).then(function (src) {
-            update_submit_area(src);
-          });
-        }
-
         $('#id_source_file').on('click change', function(e) {
           var file = $(this)[0].files[0];
           if (file) {
             if (file.name.endsWith('zip')) {
               update_submit_area(file.name);
             }
-            {% if output_only %}
-              else if (file.name.endsWith('sb3')) {
-                update_submit_area(file.name);
-              }
-            {% else %}
-              else if (file.name.endsWith('sb3')) {
-                get_source_scratch(file);
-              }
-            {% endif %}
+            else if (file.name.endsWith('sb3')) {
+              update_submit_area(file.name);
+            }
             else {
               get_source_default(file);
             }