source: extensions/Autosize/js/JScript.js @ 22360

function getScrollMaxY() {
  var innerh;
  if (window.innerHeight) {
    innerh = window.innerHeight;
  } else {
    innerh = document.body.clientHeight;
  }
  if (window.innerHeight && window.scrollMaxY) {
    // Firefox     
    yWithScroll = window.innerHeight + window.scrollMaxY;
  } else if (
     document.body.scrollHeight > document.body.offsetHeight) {
    // all but Explorer Mac    
    yWithScroll = document.body.scrollHeight;
  } else {
    // works in Explorer 6 Strict, Mozilla (not FF) and Safari   
    yWithScroll = document.body.offsetHeight;
  }
  return yWithScroll - innerh;
}


jQuery(document).ready(function (jQuery) {
  jQuery(window).load(function () {  
    if (jQuery("#scrolltotop").length == 0)
      jQuery('#scrolltobottom').before('<div id="scrolltotop" ><a title="Revenir en haut de la page" href="#"></a></div>');

    stb = jQuery('#scrolltobottom');
    stt = jQuery('#scrolltotop');
    stt.css('opacity', 1);
    stb.css('opacity', 1);

    jQuery('#scrolltotop').height(100);
    jQuery('#scrolltobottom').height(100);
    jQuery('#scrolltotop').css({
    });
    jQuery('#scrolltobottom').css({
    });
    jQuery(window).resize(
               function (event, ui) {
                 jQuery(window).scroll();
               });
    jQuery('.auto_details').text(" ");

    wmax = jQuery("body").height() - jQuery(window).height();
    scrollTop = jQuery(window).scrollTop();
    pourcent = (scrollTop / wmax);
    jQuery(stt).css({ opacity: pourcent });
    jQuery(stb).css({ opacity: 1 - pourcent });

    //===================================================               
    jQuery(window).scroll(function () {
      maxi = getScrollMaxY();
      wmax = jQuery("body").height() - jQuery(window).height();
      scrollTop = jQuery(window).scrollTop();
      pourcent = (scrollTop / wmax);


      jQuery(stt).css({ opacity: pourcent });
      jQuery(stb).css({ opacity: 1 - pourcent });


      jQuery("#scrollmiddle").css("bottom", maxi + "px");
      // jQuery("#scrollmiddle").text(pourcent);
      //====================================================
      scrollBottom = jQuery(window).scrollTop();

    });
    //=====================================================
    jQuery('#scrolltobottom a').mouseover(function () {
      wmax = jQuery("body").height() - jQuery(window).height();
      scrollTop = jQuery(window).scrollTop();
      pourcent = (scrollTop / wmax);

      stb.stop().fadeTo(500, 1 - pourcent);

    });
    jQuery('#scrolltobottom a').mouseout(function () {
      stb.stop().fadeTo(500, 0);

    });
    jQuery('#scrolltotop a').mouseover(function () {
      wmax = jQuery("body").height() - jQuery(window).height();
      scrollTop = jQuery(window).scrollTop();
      pourcent = (scrollTop / wmax);
      stt.stop().fadeTo(500, pourcent);

    });
    jQuery('#scrolltotop a').mouseout(function () {
      stt.stop().fadeTo(500, 0);
    });

    jQuery('#scrolltobottom a').click(function () {
      pos = jQuery("body").height() - jQuery(window).height(); ;
      jQuery('html, body').animate({
        scrollTop: pos + 'px'
      }, 1000, function () {

      });
    });

    jQuery('#scrolltotop a').click(function () {
      pos = 0;
      jQuery('html, body').animate({
        scrollTop: pos + 'px'
      }, 0, function () {


      });
    });
    //===================================================================         



  });
}); 
//=========================================================