There are many reasons why you may want to disable a form's submit button to prevent entries from being sent from the browser. For example, perhaps you've created a simple calculator form or a demo form for a specific Formidable feature as we do throughout this site. The solution we use is to modify the submit button code on the form's Customize HTML page in the form's settings. This is the code we use:
There are two changes to Formidable's default code in this example. The first is the style="display:none;" added to the div with the frm_submit class. The second is the "disabled" directive added to the submit button code. If you don't disable the submit button, entries will be sent if the user presses their return key.