Currently I am trying to do some customization on SharePoint. On a form I would like to do some form validation while pressing the save button. The save button has a default on_click javascript event which I can't touch. I would like to set a field value while clicking the button.

For some reason the on_click event event is triggered before the jQuery click event and the form is already submitted before jQuery could set the field value.

Is there a possibility to trigger the click event before the on_click event?