关于HTTP GET与POST方法的困惑：POST请求为何能获取GET参数

Great question! This is a super common misunderstanding about HTTP request methods and parameters—let’s clear it up step by step.

First, a critical correction: HTTP methods and URL query params are independent #

You might have thought GET and POST are mutually exclusive when it comes to parameter sources, but that’s not how HTTP works. Here’s the breakdown:

• URL query parameters (the stuff after ? in your URL) are part of the URL itself, regardless of whether you’re sending a GET or POST request. PHP parses these into the $_GET superglobal no matter what request method is used.
• POST body parameters (your form data) are sent in the request’s body (not the URL), and PHP parses these into $_POST when the request method is POST (and the content type is application/x-www-form-urlencoded or multipart/form-data, which is standard for form submissions).

What’s happening in your test case #

When you loaded http://localhost/testing/index.php?getname=someget and then submitted the POST form, your browser sent the POST request to the same URL—including the ?getname=someget query string. So:

1. The server sees the URL query string getname=someget and populates $_GET['getname'].
2. The server also sees the POST body data (like posttitle=...) and populates $_POST['posttitle'].

There’s no conflict here because these two parameter sets come from entirely different parts of the HTTP request.

A quick test to confirm #

Try modifying your form’s action attribute to point to index.php (without the query string), then submit it. You’ll find that $_GET['getname'] is no longer available, but $_POST['posttitle'] still is. That proves the query string is purely tied to the URL, not the request method.

Bonus: Can GET requests have body data? #

For completeness—yes, technically a GET request can include a body, but HTTP standards discourage it, and PHP won’t parse that body into $_POST (since $_POST is reserved for POST request bodies). But that’s a separate edge case!

内容的提问来源于stack exchange，提问作者Shilan Titaju