PHP url_php tips for capturing the top two pages by hiding form controls

I have encountered similar problems in my learning process:
For example, backstage is want to make this kind of son:

But the reality is this:

Workaround:
By hiding form controls

<input type= "hidden" name= "Prevurl" value= "<?php echo $_server[' http_referer '"]?> ">

So the value of $_server[' Http_referer ' appears to be temporarily deposited in $_post[prevurl].

In fact, the principle of this method is to put the previous URL through the Post method to the other place, but this post is the current page

In later development, the section of the new article will have a select tag, and if you enable the disabled of the SELECT tag, you will not post the value you selected, so I once again use the hidden cheat method, secretly submitted once, tried and true.