diff --git a/planetstack/templates/admin/core/slice/change_form.html b/planetstack/templates/admin/core/slice/change_form.html
index c94b580..e97364b 100644
--- a/planetstack/templates/admin/core/slice/change_form.html
+++ b/planetstack/templates/admin/core/slice/change_form.html
@@ -8,6 +8,13 @@
 {% endfor %}
 ];
 
+sites = [
+{% for s in sites %}
+  [{{ s.0 }}, {{ s.1 }}],
+{% endfor %}
+];
+ 
+
 function update_nodes(deployment_select, node_select_id) {
     deployment_id = $(deployment_select).val();
     html = "<option value=''>---------</option>\n";
@@ -20,6 +27,15 @@
     //console.log(html);
     $("#"+node_select_id).empty().append(html);
 }
+
+function update_slice_prefix(site_select, slice_name_id) {
+    site_id = $(site_select).val();
+    slice_prefix="";
+    if (site_id in sites) {
+        slice_prefix=sites[site_id]+"_";
+    }
+    $("#"+slice_name_id).val(slice_prefix); 
+}
 </script>
 
 {% endblock %}