Description:
------------
In Class can't indirect use $_GET、$_POST etc;

Test script:
---------------
$_GET['yk'] = 'aabb';
$get = '_GET';
$tmp = $$get;
echo $tmp['yk'];     //right

class yk{
	
	public function get(){
		$get = '_GET';
		$tmp = $$get;
		echo $tmp['yk'];
	}
	
	public function get2(){
		$get = 'Atmp';
		$Atmp = 'bbaa';
		$tmp = $$get;
		echo $tmp;
	}
}

$yk = new yk();
$yk->get();   //error  Undefined variable: _GET