How to Fix Web-To-Lead Duplicate via Multiple Click of Submit Button

How to Fix Web-To-Lead Duplicate via Multiple Click of Submit Button

When a lead is on the web-to-lead form on website and fills out information, if they click SUBMIT more than once, it will submit more than one lead to CRM.

I DONT want to prevent a lead from being able to be submitted twice (on different "occasions") but I DO want to prevent them from submitting the same submissions twice.

Is there some code I can add to disable the submit button after it's been clicked one time?