$cat = array();

for($f=1;$f<100;$f++)
{ echo "1";
	if(!array_key_exists('cattag'.$f.'_1_1', $_POST))
        { echo "2";
                
				break;
        }
		
        for($g=1;$g<100;$g++)
        {  echo "3";
                if(!array_key_exists('cattag'.$f.'_'.$g.'_1', $_POST))
                { echo "4";
                      
						break;
                }
				
                       
              $cat[$f][$g] = $_POST['cattag'.$f.'_'.$g.'_1'];
							
                        
                
        }
}





(post dump)

array(7) {
  
  ["cattag_1_1_1"]=>
  string(2) "22"
  ["Submit"]=>
  string(6) "Submit"
}