How to read the query string in PHP and HTML?

a URL ending with something like portal.php?key2=hello how can I get 开发者_如何学编程the value of "key2"?

$_GET['key2']

will get you the value from a query string.

$_POST['key2']

will get you the value from a form posted.

$_REQUEST['key2']

will get you either of the above if it exists.

var_dump( $_GET['key2'] );

GET data is decoded into the $_GET super-global array. See http://php.net/manual/en/language.variables.external.php