Code for custom Register button

Hello,
I want to make a custom "Register" button for my event pages. What do I put in the button attributes to make it work?

normally when I do this, i simply redirect to another page. But, since it's using Javascript, I'm not sure what and where to put it. Pleae advise. Thanks.

Custom "Register" button? Could you please explain more details ? You will have to edit the code if you want to change something.

Please send me the link to the page so that I can tell you what files you need to change

Regards,

Tuan