$(document).ready(function(){
  var panel4_currentPosition = 0;
  var panel4_slideWidth = 600;
  var panel4_slides = $('.panel4_slide');
  var panel4_numberOfSlides = panel4_slides.length;

  // Remove scrollbar in JS
  $('#panel4_slideshow').css('overflow', 'hidden');
  $('#panel4_slideshow').css('width', '580px');
  $('.ninesixty .panel .details').css('width', '330px');
  $('.ninesixty .panel #panel4_slideshow').css('width', '580px');

  // Wrap all .slides with #slideInner div
  panel4_slides
  .wrapAll('<div id="panel4_slideInner"></div>')
  // Float left to display horizontally, readjust .slides width
  .css({
    'float' : 'left',
    'width' : panel4_slideWidth
  });

  // Set #slideInner width equal to total width of all slides
  $('#panel4_slideInner').css('width', panel4_slideWidth * panel4_numberOfSlides);

  // Insert left and right arrow controls in the DOM
  $('.ninesixty #panel4 .link')
  	.append('<div id="panel4_slideshow_controls"><span class="panel4_control" id="panel4_previous">Previous</span><span class="panel4_control" id="panel4_next">Next</span></div>');

  // Hide left arrow control on first load
  manageControls(panel4_currentPosition);

  // Create event listeners for .controls clicks
  $('.panel4_control')
    .bind('click', function(){
    // Determine new position
      panel4_currentPosition = ($(this).attr('id')=='panel4_next')
    ? panel4_currentPosition+1 : panel4_currentPosition-1;

      // Hide / show controls
      manageControls(panel4_currentPosition);
      // Move slideInner using margin-left
      $('#panel4_slideInner').animate({
        'marginLeft' : panel4_slideWidth*(-panel4_currentPosition)
      });
    });

  // manageControls: Hides and shows controls depending on currentPosition
  function manageControls(position){
    // Hide left arrow if position is first slide
    if(position==0){ $('#panel4_previous').hide() }
    else{ $('#panel4_previous').show() }
    // Hide right arrow if position is last slide
    if(position==panel4_numberOfSlides-1){ $('#panel4_next').hide() }
    else{ $('#panel4_next').show() }
    }
  });