var first = 0;
var show = 5;
var max = 8;

function setImage(direction, toggle) {
  var node = document.getElementById('leftnav');
  if (direction == 'R') {
    node = document.getElementById('rightnav');
  }
  if (toggle == 1) {
    if (direction == 'R') {
      if ((first+show) > max) {
        node.src="http://www.all.org/images/all3/mediabar/media_right_disabled.png";
      } else {
        node.src="http://www.all.org/images/all3/mediabar/media_right_on.png";
      }
    } else {
      if (first == 0) {
        node.src="http://www.all.org/images/all3/mediabar/media_left_disabled.png";
      } else {
        node.src="http://www.all.org/images/all3/mediabar/media_left_on.png";
      }
    }
  } else {
    if (direction == 'R') {
      if ((first+show) > max) {
        node.src="http://www.all.org/images/all3/mediabar/media_right_disabled.png";
      } else {
        node.src="http://www.all.org/images/all3/mediabar/media_right.png";
      }
    } else {
      if (first == 0) {
        node.src="http://www.all.org/images/all3/mediabar/media_left_disabled.png";
      } else {
        node.src="http://www.all.org/images/all3/mediabar/media_left.png";
      }
    }
  }
}

var firstbox = '';
var lastbox = ''
var step = 0;
var slide_direction = '';

function slide() {
  if (slide_direction == 'R') {
    if (step == 0) {
      lastbox.style.display = '';
    }
    if (step <= 150) {
      firstbox.style.width = (150 - step) + 'px';
      step = step + 10;
      setTimeout("slide()", 25);
    } else {
      step = 0;
      firstbox.style.width = '0px';
      firstbox.style.display = 'none';
      lastbox.style.width = '150px';
    }
  } else {
    if (step == 0) {
      firstbox.style.display = '';
    }
    if (step <= 150) {
      firstbox.style.width = step + 'px';
      step = step + 10;
      setTimeout("slide()", 25);
    } else {
      step = 0;
      firstbox.style.width = '150px';
      lastbox.style.width = '0px';
      lastbox.style.display = 'none';
    }
  } 
}

function moveDiv(direction) {
  if (step != 0) {
    step = 160;
    slide();
  }
  var lnode = document.getElementById('leftnav');
  var rnode = document.getElementById('rightnav');
  if (direction == 'R') {
    if ((first + show) <= max) {
      firstbox = document.getElementById("box_"+first);
      lastbox = document.getElementById("box_"+(first+show));
      step = 0;
      slide_direction = 'R';
      slide();
      first = first + 1;
      if ((first+show) == max) {
        rnode.src="http://www.all.org/images/all3/mediabar/media_right_disabled.png";
      } else {
        rnode.src="http://www.all.org/images/all3/mediabar/media_right.png";
      }
    }
    lnode.src="http://www.all.org/images/all3/mediabar/media_left.png";
  } else {
    if (first > 0) {
      firstbox = document.getElementById("box_"+(first-1));
      lastbox = document.getElementById("box_"+(first+(show-1)));
      step = 0;
      slide_direction = 'L';
      slide();
      first = first - 1;
      rnode.src="http://www.all.org/images/all3/mediabar/media_right.png";
      if (first == 0) {
        lnode.src="http://www.all.org/images/all3/mediabar/media_left_disabled.png";
      } else {
        lnode.src="http://www.all.org/images/all3/mediabar/media_left.png";
      }
    }
  }
}