How to freez/readonly strings of textarea on condition

Hi Everyone,
I have created Textarea field, once data is entered by the any user, next time when some other user try to edit that textarea field  it can be editable but old text area data given should not be removed (i'e freez)but can be extended.

Does anyone have any idea on how to implement this logic??

Thank you,

  • We use the concept of "work log" and "latest update":

    The user is allowed to enter data in the "Latest Update" field, when the record is saved the data is prepended to the Work Log (latest update first) with a timestamp and the user name. (the timestamp code can be improved)

    The Work Log is read-only for all users. After it is copied, the "Latest Update" is cleared so that field is always empty.

    A before_save logic hook takes care of copying the data from the Latest Update to the Work Log.

      function update_log($bean,$event,$arguments) {
        if(!empty($bean->latest_update_c)) {
          global $current_user;
          $timedate = new TimeDate;
          $date = $timedate->to_display_date_time(gmdate("Y-m-d H:i:s", gmmktime() ),true,true, $current_user);
          $bean->work_log_c = $date ." - " . $current_user->user_name . ": " . $bean->latest_update_c . "\n" . $bean->work_log_c;
          $bean->latest_update_c = '';
        }
      }

    Hope this helps,
    FrancescaS