Slideshow from directory index

slides.js

((function(){
  if(typeof window.jQuery == 'undefined') {
    var script = document.createElement('script');
    script.setAttribute('src','//ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js');
    document.getElementsByTagName('head')[0].appendChild(script);
    var attempts = 15;
    ;(function(){
      if(typeof window.jQuery == 'undefined') {
        if(--attempts > 0) {
          window.setTimeout(arguments.callee, 250);
        } 
      } else {
  init();
      }
    })();
  }
function init() {
 j = jQuery;
 var links = j('a[href$=".gif"], a[href$=".jpg"], a[href$=".png"]');
 var image_list = links.map(function() {return j(this).attr('href')});
 var current = 0;
 var last = image_list.length-1;
 var container = j('<div class="container"></div>');

 j('body').empty().append(container);
 j(document).keyup(function(e) {
  if(e.keyCode == 37) prev();
  else if(e.keyCode == 39) next();
 });
 set_image(0);
 function prev() {
  if(current==0) current = last;
  else current--;
  set_image(current);
 }
 function next() {
  if(current==last) current=0;
  else current++;
  set_image(current);
 }
 function set_image(i) {
  j('.container').empty().append('<img src="'+image_list[i]+'"/>');
 }
}
})();