adding URL parameters to a form PHP HTML

Question

Is it okay or correct to put a url get parameter in a form action?

<form method='get' action='index.php?do=search'>
  <input name='_search' type='text' value='What are you looking for?'>
  <button type='submit'> Search </button>
</form>

When I submit the form the URL is changed to:

index.php?_search=What are you looking for? (I've stripped %20)

I'd prefer the URL to read

index.php?do=search&_search=What are you looking for?

Would it be best to add a hidden field into the form

<input type='hidden' name='do' value='search' />

Answer 1

In my opinion you should add them as hidden fields. There is no point to try to pass params if you can do it via hidden form field

use that:

<input type='hidden' name='do' value='search' />