var scroller=null;var scrollposition=0;function scrollstart(steps)
{var stop=false;scrollposition+=steps;if(scrollposition>0)
{scrollposition=0;stop=true;}
if(scrollposition<-(overlay_scroll.offsetWidth-overlay_scroll.parentNode.offsetWidth))
{scrollposition=-(overlay_scroll.offsetWidth-overlay_scroll.parentNode.offsetWidth);document.getElementById("overlay_thumb_pfeil_rechts").style.backgroundImage="url(images/lightbox/pfeil_right_inaktiv.png)";stop=true;}
else
{document.getElementById("overlay_thumb_pfeil_rechts").style.backgroundImage="url(images/lightbox/pfeil_right.png)";}
overlay_scroll.style.left=scrollposition+"px";if(scrollposition<0)
{document.getElementById("overlay_thumb_pfeil_links").style.backgroundImage="url(images/lightbox/pfeil_left.png)";}
else
{document.getElementById("overlay_thumb_pfeil_links").style.backgroundImage="url(images/lightbox/pfeil_left_inaktiv.png)";}
if(stop==false)
{if(steps>0)
{document.getElementById("overlay_thumb_pfeil_links").style.backgroundImage="url(images/lightbox/pfeil_left_over.png)";}
else
{document.getElementById("overlay_thumb_pfeil_rechts").style.backgroundImage="url(images/lightbox/pfeil_right_over.png)";}
scroller=setTimeout("scrollstart("+steps+")",20);}
else
{scrollstop();}}
function scrollstop()
{if(scrollposition<=-(overlay_scroll.offsetWidth-overlay_scroll.parentNode.offsetWidth))
{document.getElementById("overlay_thumb_pfeil_rechts").style.backgroundImage="url(images/lightbox/pfeil_right_inaktiv.png)";}
else
{document.getElementById("overlay_thumb_pfeil_rechts").style.backgroundImage="url(images/lightbox/pfeil_right.png)";}
if(scrollposition<0)
{document.getElementById("overlay_thumb_pfeil_links").style.backgroundImage="url(images/lightbox/pfeil_left.png)";}
else
{document.getElementById("overlay_thumb_pfeil_links").style.backgroundImage="url(images/lightbox/pfeil_left_inaktiv.png)";}
clearTimeout(scroller);}