Simple PHP GET question

UPDATE:

All the methods given below doesn't

work for:

mysite.com?username=me&action=editpost

but only for:

mysite.com?action=editpost

I know how to detect if a particular GET method is in the url:

$username = $_GET['username'];

if ($username) {
   // whatever
}

But how can I detect something like this:

http://www.开发者_开发百科mysite.com?username=me&action=editpost

How can I detect the "&action" above?

$action = $_GET['action'];

if ($action) {
   // whatever
}

or

if(array_key_exists('action', $_GET)) {

}

Btw the method is called GET. What you mean are parameters.

All GET parameters are accessible in the same way.

$username = $_GET['username'];
$action = $_GET['action'];

if ($username) {
   // whatever
}

if ($action == 'editpost') {
   // whatever
}

array_key_exists('action', $_GET)

if (array_key_exists('action', $_GET) && $action = $_GET['action']) {
 // action exists
}

However, if an empty string (or anything that evaluates to boolean false) is a valid value, just use this instead:

if (isset($_GET['action'])) {
 $action= $_GET['action'];
 // Do stuff with $action
}

Using $_GET['action'] when action has not been set will generate a notice, depending on the error reporting level.

You can do the following:

if(array_key_exists('action', $_GET)){ // returns a boolean
  // do something
}

The same way - $_GET is an array

$action = $_GET['action'];

Try print_r( $_GET ) to see what's in it

the parameters in the url are assigned to $_GET array from left to the right.

If you have something like

?username=me&action=editpost&somekey=somevalue&action=&someotherkey=someothervalue

then first 'editpost' will be assigned as action but then it will be replaces as '' and as a result

$_GET['action'] = ''; (instead of 'editpost')

The same way as username:

$action = $_GET['action'];