title: javascript input via native popup
body: <p>In the past, I've seen javascript <code>alert()</code> style popups but they had input fields in them.</p>
  
  <p>These forms are much like the primitive username/password field inputs you see when an <code>.htpasswd</code> file is used.</p>
  
  <p>Can someone tell me how to implement this using regular javascript? (No libraries please)</p>