Question

I want to load these two files

<link rel="stylesheet" type="text/css" href="sewmuchcss.css">
<script type="text/javascript" src="sewmuchjs.js"></script>        

in my header only when a user presses “up, up down, down, left, right, left, right.” How would I go about accomplishing this? Would I use jquery, or javascript. What would I have to do?
Thanks in advance for any help or answers.

Answer 1

I would use jQuery, and you can use the following algorithm to check for the multiple keys in a row:

var keysPressed = [];
                       //  U,  U,  D,  D,  L,  R,  L,  R
var MAGIC_KEY_SEQUENCE = [ 38, 38, 40, 40, 37, 39, 37, 39 ]

$('body').on('keydown',function(e){
     var code = (e.keyCode ? e.keyCode : e.which);

     keysPressed.push( code );

     if ( keysPressed[ keysPressed.length - 1 ] == MAGIC_KEY_SEQUENCE[ keysPressed.length - 1 ] )
     {
       // so far so good

       if ( keysPressed.length == MAGIC_KEY_SEQUENCE.length )
       {
         // all keys were pressed in the right order!
         alert( 'hurray!' );

         $('<link/>').attr({
             rel:'stylesheet',
             type:'text/css',
             href:'sewmuchcss.css'}).appendTo('head');
         $.getScript('sewmuchjs.js');
       }
     }
     else
     {
       // something didn't match, so reset the list
       keysPressed = []       
     }
})​

Play with it here:
http://jsfiddle.net/japanick/vfRqk/