| Lines 23-28
          $(document).ready(function() {
      
      
        Link Here | 
        
          | 23 |                 alert(_("The destination should be filled.")); | 23 |                 alert(_("The destination should be filled.")); | 
        
          | 24 |                 return false; | 24 |                 return false; | 
        
          | 25 |             } | 25 |             } | 
            
              |  |  | 26 |             if ( ( $("#to_field").val()   <= 10 && $("#to_subfield").val().length   > 0 ) || | 
            
              | 27 |                  ( $("#from_field").val() <= 10 && $("#from_subfield").val().length > 0 ) ) { | 
            
              | 28 |                  alert(_("If the field is a control field, the subfield should be empty")); | 
            
              | 29 |                  return false; | 
            
              | 30 |             } | 
            
              | 31 |             if ( ( $("#from_field").val() <= 10 && $("#to_subfield").val().length   == 0 ) || | 
            
              | 32 |                  ( $("#to_field").val()   <= 10 && $("#from_subfield").val().length == 0 ) ) { | 
            
              | 33 |                 alert(_("A control field cannot be used with a regular field.")); | 
            
              | 34 |                 return false; | 
            
              | 35 |              } | 
        
          | 26 |         } | 36 |         } | 
        
          | 27 |         if ( action == 'update_field' ) { | 37 |         if ( action == 'update_field' ) { | 
        
          | 28 |             if ( $("#from_subfield").val().length <= 0 ) { | 38 |             if ( $("#from_subfield").val().length <= 0 ) { | 
            
              | 29 | -  |  |  |