var SLIDETIMER = 3;
var SLIDESPEED = 5;
var SCROLLTIMER = 3;
var SCROLLSPEED = 3;
var STARTINGOPACITY = 40;

// handles section to section scrolling of the content //
function slideContent(id,prefix,timer) {
  var div = document.getElementById(id);
  var slider = div.parentNode;
  clearInterval(slider.timer);
  slider.section = parseInt(id.replace(/\D/g,''));
  slider.target = div.offsetTop;
  slider.style.top = slider.style.top || '0px';
  slider.current = slider.style.top.replace('px','');
  slider.direction = (Math.abs(slider.current) > slider.target) ? 1 : -1;
  slider.style.opacity = STARTINGOPACITY * .01;
  slider.timer = setInterval( function() { slideAnimate(slider,prefix,timer) }, SLIDETIMER);
}

function slideAnimate(slider,prefix,timer) {
  var curr = Math.abs(slider.current);
  var tar = Math.abs(slider.target);
  var dir = slider.direction;
  if((tar - curr <= SLIDESPEED && dir == -1) || (curr - tar <= SLIDESPEED && dir == 1)) {
    slider.style.top = (slider.target * -1) + 'px';
	slider.style.opacity = 1;
    clearInterval(slider.timer);
	if(slider.autoscroll) {
	  setTimeout( function() { autoScroll(slider.id,prefix,timer) }, timer * 750);
	}
  } else {
	var pos = (dir == 1) ? parseInt(slider.current) + SLIDESPEED : slider.current - SLIDESPEED;
    slider.current = pos;
    slider.style.top = pos + 'px';
  }
}

// handles manual scrolling of the content //
function scrollContent(id,dir) {
  var div = document.getElementById(id);
  clearInterval(div.timer);
  var sections = div.getElementsByTagName('div');
  var length = sections.length;
  var limit;
  if(dir == -1) {
    limit = 0;
  } else {
    if(length > 1) {
      limit = sections[length-1].offsetTop;
    } else {
      limit = sections[length-1].offsetHeight - div.parentNode.offsetHeight + 20;
    }
  }
  div.style.opacity = STARTINGOPACITY * .01;
  div.timer = setInterval( function() { scrollAnimate(div,dir,limit) }, SCROLLTIMER);
}

function scrollAnimate(div,dir,limit) {
  div.style.top = div.style.top || '0px';
  var top = div.style.top.replace('px','');
  if(dir == 1) {
	if(limit - Math.abs(top) <= SCROLLSPEED) {
	  cancelScroll(div.id);
	  div.style.top = '-' + limit + 'px';
	} else {
	  div.style.top = top - SCROLLSPEED + 'px';
	}
  } else {
	if(Math.abs(top) - limit <= SCROLLSPEED) {
	  cancelScroll(div.id);
	  div.style.top = limit + 'px';
	} else {
	  div.style.top = parseInt(top) + SCROLLSPEED + 'px';
	}
  }
}

// cancel the scrolling on mouseout //
function cancelScroll(id) {
  var div = document.getElementById(id);
  div.style.opacity = 1;
  clearTimeout(div.timer);
}

// initiate auto scrolling //
function autoScroll(id,prefix,timer,restart) {
  var div = document.getElementById(id);
  div.autoscroll = (!div.autoscroll && !restart) ? false : true;
  if(div.autoscroll) {
    var sections = div.getElementsByTagName('div');
    var length = sections.length;
    div.section = (div.section && div.section < length) ? div.section + 1 : 1;
    slideContent(prefix + '-' + div.section,prefix,timer);
  }
}

// cancel automatic scrolling //
function cancelAutoScroll(id) {
  var div = document.getElementById(id);
  div.autoscroll = false;
}

// tabs


    var tabLinks = new Array();
    var contentDivs = new Array();

    function init() {

      // Grab the tab links and content divs from the page
      var tabListItems = document.getElementById('tabs').childNodes;
      for ( var i = 0; i < tabListItems.length; i++ ) {
        if ( tabListItems[i].nodeName == "LI" ) {
          var tabLink = getFirstChildWithTagName( tabListItems[i], 'A' );
          var id = getHash( tabLink.getAttribute('href') );
          tabLinks[id] = tabLink;
          contentDivs[id] = document.getElementById( id );
        }
      }

      // Assign onclick events to the tab links, and
      // highlight the first tab
      var i = 0;

      for ( var id in tabLinks ) {
        tabLinks[id].onmouseover = showTab;
        tabLinks[id].onclick = showTab;
        tabLinks[id].onfocus = function() { this.blur() };
        if ( i == 0 ) tabLinks[id].className = 'selected';
        i++;
      }

      // Hide all content divs except the first
      var i = 0;

      for ( var id in contentDivs ) {
        if ( i != 0 ) contentDivs[id].className = 'tabContent hide';
        i++;
      }
    }

    function showTab() {
      var selectedId = getHash( this.getAttribute('href') );

      // Highlight the selected tab, and dim all others.
      // Also show the selected content div, and hide all others.
      for ( var id in contentDivs ) {
        if ( id == selectedId ) {
          tabLinks[id].className = 'selected';
          contentDivs[id].className = 'tabContent';
        } else {
          tabLinks[id].className = '';
          contentDivs[id].className = 'tabContent hide';
        }
      }

      // Stop the browser following the link
      return false;
    }

    function getFirstChildWithTagName( element, tagName ) {
      for ( var i = 0; i < element.childNodes.length; i++ ) {
        if ( element.childNodes[i].nodeName == tagName ) return element.childNodes[i];
      }
    }

    function getHash( url ) {
      var hashPos = url.lastIndexOf ( '#' );
      return url.substring( hashPos + 1 );
    }