Our display business rule script is very simple. It just captures time worked and sets a g_scratchpad variable to the value of time worked before the form is opened :

(function executeRule(current, previous /*null when async*/) {

  g_scratchpad.time_worked_inc = current.time_worked.dateNumericValue();

  ///gs.log('time: '+ current.time_worked.dateNumericValue(),'time');

})(current, previous);

Here is the onSubmit Client Script. We have it only running on certain action types (when someone saves or updates):

function onSubmit() {

  ///get the value of time worked as the user tries to update/save thee form

  var timer = g_form.getIntValue('time_worked');

  //multiply time worked integer value by 1000

  var dateNumeric = timer * 1000;

  //get the name of the action the user is performing, we only want to prevent someone from updating or saving if there is not time worked

  var action = g_form.getActionName();

  //if the user's action is update or save, make sure they entered time worked, and if not, prompt an alert message

  if (action == 'sysverb_update' || action == 'sysverb_update_and_stay'){

  var diff = dateNumeric - g_scratchpad.time_worked_inc;

  if(diff == 0){

  alert('Please enter Time Worked before updating Incidents. Thank You.');

  return false;

  }

  }

}