I would like to implement a function to highlight, underline or caption blank mandatory fields. I have implemented the functionality of the modal window appearing only when all mandatory fields are filled in, but I would like that if optional fields are not filled in, the modal window would not just not open, but also shake the button smoothly, highlight or sign or shake the fields that are not filled in and the modal window would appear only when all mandatory fields are filled in, I would also like to realize the playback of a one or two second sound ONLY when all mandatory fields are filled in and the modal opens, this is just a mockup, this form is not sent anywhere, this is just an additional functionality, I would be grateful for your help.
Here is the link on the CodePen CodePen
I tried only to create the audio playback functionality, but the modal didn't appear or the page reloaded.
Thanks for helping me!
