Redirect to user user defined location

I'm trying to write a form in which user writes a location and the page redirects there after submit. How can I accomplish that? I have problem to find out how to put something to action="" when I do not know the value yet. Something with this logic:

 <form action="how-to-get-this-value">
   <input name="location" type="text">
   <input name="submit" type="submit">
 </form>

I can use whatever I want to do this (javascript, css, php...).