function MM_openBrWindow(theURL,winName,features) { //v2.0
  window.open(theURL,winName,features);
}

function setSoundState(state)
{
    var img = new Image(1,1);
    img.src = '/SetSoundState.aspx?sound=' + state;
}

function trackDownload(chapterNumber)
{
    var axel = Math.random() + "";
    var a = axel * 10000000000000;
    var src = "http://fls.doubleclick.net/activityi;src=1009935;type=knowi257;cat=downl831;u1=" + chapterNumber + ";ord=" + a + "?";
    //alert(src);
    //document.write('<IFRAME SRC="' + src + '" WIDTH=1 HEIGHT=1 FRAMEBORDER=0></IFRAME>');
    var oFrame = document.getElementById("trk"); 
    oFrame.src = src;
}