Embedding Sound in Web Pages, Part II: The Full Script - Doc JavaScript

The Full Script

The Jukebox script is included below. We have not explained two items of the script. First, the init() function. It is triggered when the document is completely loaded. It sets the loaded variable for future verifications by the control functions of the Jukebox. It also sets the volume at mid point. Secondly, we have not discussed the <EMBED> tag. See Column 20 for datails on this sound embedding tag.

<SCRIPT LANGUAGE="JavaScript1.1">
<!--
var NSsound = navigator.plugins && navigator.plugins["LiveAudio"]
  && navigator.javaEnabled(); // join with previous line
var IEsound = navigator.plugins && document.all;
var curVolume = 5;
var timerID = null;
var intervalID = null;
var sliding = false;
var ready = false;
var shouldPlay = false;
var loaded = false;
var songs = new Array();
songs[0] = new makeSong("eleanor.mid", "Eleanor");
songs[1] = new makeSong("girl.mid", "Girl");
songs[2] = new makeSong("michelle.mid", "Michelle");
songs[3] = new makeSong("sheway.mid", "She's Got a Way");
songs[4] = new makeSong("wholenew.mid", "A Whole New World");
var NSvolume = new Array();
for (var i = 0; i <= 10; i++) {
  NSvolume[i] = i * 10;
}
var IEvolume = new Array();
IEvolume[0] = -10000;
IEvolume[1] = -4500;
IEvolume[2] = -4000;
IEvolume[3] = -3500;
IEvolume[4] = -3000;
IEvolume[5] = -2500;
IEvolume[6] = -2000;
IEvolume[7] = -1500;
IEvolume[8] = -1000;
IEvolume[9] = -500;
IEvolume[10] = 0;
function makeSong(url, name) {
	this.url = url;
	this.name = name;
}
function changeVolume(step) {
  if (!loaded) return;
  var newVolume = curVolume + step;
  if ((newVolume >= 0) && (newVolume <= 10))
    setVolume(newVolume);
  else if (sliding)
    stopSlide();
}
function setVolume(vol) {
  if (!loaded) return;
  curVolume = vol;
  if (NSsound)
    document.jukebox.setvol(NSvolume[vol])
  else
    document.jukebox.volume = IEvolume[vol];
  for (var i = 0; i < 10; i++) {
    document.images["vol" + i].src = (i < vol) ? on.src : off.src;
  }
}
function startSlide(direction) {
  changeVolume(direction);
  timerID = setTimeout("slideVolume(" + direction + ")", 500);
  return false;
}
function slideVolume(direction) {
  sliding = true;
  intervalID = setInterval("changeVolume(" + direction + ")", 50);
}
function stopSlide() {
  if (intervalID) clearInterval(intervalID);
  if (timerID) clearTimeout(timerID);
  sliding = false;
}
function display(text) {
  if (IEsound) event.srcElement.style.cursor = "hand";
  window.status = text;
  return true;
}
function pause() {
  if (!loaded) return;
  shouldPlay = false;
  document.jukebox.pause();
}
function stop() {
  if (!loaded) return;
  shouldPlay = false;
  document.jukebox.stop();
}
function play() {
  if (!loaded) return;
  if (NSsound) ready = document.jukebox.IsReady();
  if (!ready) {
    alert("The audio file hasn't loaded yet.");
    return;
  }
  var list = document.jukeboxform.songs;
  var songURL = list.options[list.selectedIndex].value;
  if (NSsound) {
    document.jukebox.play(false, songURL)
  } else
    document.jukebox.play();
}
function change() {
  if (!loaded) return;
  var list = document.jukeboxform.songs;
  var songURL = list.options[list.selectedIndex].value;
  document.jukebox.stop();
  if (NSsound)
    document.jukebox.play(false, songURL)
  else {
    document.jukebox.filename = songURL;
    shouldPlay = true;
  }
}
function init() {
  loaded = true;
  setVolume(curVolume);
}
function makeVolume() {
  var str = "";
  for (var i = 9; i >= 0; i--) {
    str +=  "<IMG SRC='" + off.src + "' HEIGHT='" +
      off.width + "' WIDTH='" + off.width + "' NAME='vol" +
      i + "'><BR>";
  }
  return str;
}
function makeControlButtons() {
  var str = "";
  str += "<FONT SIZE='2' COLOR='#ffffff'>Control</FONT><BR>";
  if (NSsound) {
    str += "<A HREF='javascript:play()' onMouseOver='return " +
      "display(\"Play\")' onMouseOut='return display(\"\")'>" +
      "<IMG SRC='play.gif' WIDTH='12' HEIGHT='9' HSPACE='2' " +
      "VSPACE='3' BORDER='0'></A>";
    str += "<A HREF='javascript:pause()' onMouseOver='return " +
      "display(\"Pause\")' onMouseOut='return display(\"\")'>" +
      "<IMG SRC='pause.gif' WIDTH='12' HEIGHT='9' HSPACE='2' " +
      "VSPACE='3' BORDER='0'></A>";
    str += "<A HREF='javascript:stop()' onMouseOver='return " +
      "display(\"Stop\")' onMouseOut='return display(\"\")'>" +
      "<IMG SRC='stop.gif' WIDTH='12' HEIGHT='9' HSPACE='2' " +
      "VSPACE='3' BORDER='0'></A>";
  } else {
    str += "<IMG SRC='play.gif' WIDTH='12' HEIGHT='9' " +
      "HSPACE='2' VSPACE='3' onClick='play()' " +
      "onMouseOver='return display(\"Play\")' " +
      "onMouseOut='return display(\"\")'>";
    str += "<IMG SRC='pause.gif' WIDTH='12' HEIGHT='9' " +
      "HSPACE='2' VSPACE='3' onClick='pause()' " +
      "onMouseOver='return display(\"Pause\")' " +
      "onMouseOut='return display(\"\")'>";
    str += "<IMG SRC='stop.gif' WIDTH='12' HEIGHT='9' " +
      "HSPACE='2' VSPACE='3' onClick='stop()' " +
      "onMouseOver='return display(\"Stop\")' " +
      "onMouseOut='return display(\"\")'>";
  }
  return str;
}
function makeVolumeButtons() {
  var str = "";
  str += "<FONT SIZE=2 COLOR='#ffffff'>Volume</FONT><BR>";
  if (NSsound) {
    str += "<A HREF='javascript:void(0)' " +
      "onClick='if (!document.layers) changeVolume(1)' " +
      "onMouseDown='startSlide(1)' onMouseUp='stopSlide()' " +
      "onMouseOver='return display(\"Increase volume\")' " +
      "onMouseOut='return display(\"\")'><IMG " +
      "SRC='volup.gif' WIDTH='9' HEIGHT='10' HSPACE='2' " +
      "VSPACE='3' BORDER='0'></A>";
    str += "<A HREF='javascript:void(0)' " +
      "onClick='if (!document.layers) changeVolume(-1)' " +
      "onMouseDown='startSlide(-1)' onMouseUp='stopSlide()' " +
      "onMouseOver='return display(\"Decrease volume\")' " +
      "onMouseOut='return display(\"\")'><IMG " +
      "SRC='voldown.gif' WIDTH='9' HEIGHT='10' HSPACE='2' " +
      "VSPACE='3' BORDER='0'></A>";
  } else {
    str += "<IMG SRC='volup.gif' WIDTH='9' HEIGHT='10' " +
      "HSPACE='2' VSPACE='3' " +
      "onMouseOver='return display(\"Increase volume\")' " +
      "onMouseOut='return display(\"\")' " +
      "onMouseDown='startSlide(1)' onMouseUp='stopSlide()'>";
    str += "<IMG SRC='voldown.gif' WIDTH='9' HEIGHT='10' " +
      "HSPACE='2' VSPACE='3' " +
      "onMouseOver='return display(\"Decrease volume\")' " +
      "onMouseOut='return display(\"\")' " +
      "onMouseDown='startSlide(-1)' onMouseUp='stopSlide()'>";
  }
  return str;
}
var off = new Image(4, 4);
off.src = "off.gif";
var on = new Image(4, 4);
on.src = "on.gif";
if (NSsound || IEsound) {
  document.write(
    "<FORM NAME='jukeboxform'>",
    "<TABLE BORDER='3'><TR><TD>",
    "<TABLE BORDER='0' CELLSPACING='0' CELLPADDING='4'>",
    "<TR><TD COLSPAN='3' BGCOLOR='#000000'>",
    "<SELECT NAME='songs' onchange='change()'>"
  );
  for (var i = 0; i < songs.length; i++) {
    document.write(
      "<OPTION VALUE='", songs[i].url, "'>",
      songs[i].name
    );
  }
  document.write(
    "</SELECT>",
    "</TD></TR>",
    "<TR><TD BGCOLOR='#000000' WIDTH='15' ALIGN='center'>",
    makeVolume(),
    "</TD><TD BGCOLOR='#000000' ALIGN='center'>",
    makeVolumeButtons(),
    "</TD><TD BGCOLOR='#000000' ALIGN='center'>",
    makeControlButtons(),
    "</TD></TR>",
    "</TABLE>",
    "</TD></TR></TABLE>",
    "</FORM>"
  );
  document.write("<EMBED SRC='eleanor.mid' NAME='jukebox' HIDDEN='true'
    LOOP='false' AUTOSTART='false' MASTERSOUND>"); // join with previous line
  onload = init;
}
// -->
</SCRIPT>
<SCRIPT LANGUAGE="JavaScript" FOR="jukebox" EVENT="ReadyStateChange(val)">
<!--
if (IEsound) {
  ready = (val == 4);
  if (ready && shouldPlay) document.jukebox.play();
}
//-->
</SCRIPT>