Fix front end to allow ppn control to remain blank

form.js

 'use strict'
 
 /**
- * Fix num cores
+ * Fix num cores, allowing blanks to remain
  */
 function fix_num_cores() {
   let node_type_input = $('#batch_connect_session_context_node_type');
   let node_type = node_type_input.val();
   let num_cores_input = $('#num_cores');
-  
-  if(node_type === ':hugemem') {
+
+  if(num_cores_input.val() === '') {
+    return;
+  }
+
+  if(node_type === 'hugemem') {
     set_ppn_owens_hugemem(num_cores_input);
   } else {
     set_ppn_owens_regular(num_cores_input);

form.yml

@@ -17,7 +17,7 @@ attributes:
     help: |
       Number of cores on node type (4 GB per core unless requesting whole
       node). Leave blank if requesting full node.
-    min: 1
+    min: 0
     max: 48
     step: 1
     id: 'num_cores'