JavaScript alert with 3 buttons

Question

I have a JavaScript alert button that appears on the website when a user is going to proceed to a signup page.

It looks something like this

Would you like

Answer 1

however you can use confirm function.. but NOT three buttons.

var r=confirm("Press a button!");
if (r==true)
  {
  x="You pressed OK!";
  }
 else
  {
  x="You pressed Cancel!";
  }