// BEGIN SWITCH DIV	
// function switchDiv()
//  this function takes the id of a div
//  and calls the other functions required
//  to show that div
//
function switchDiv(div_id)
{
  var style_sheet = getStyleObject(div_id);
  if (style_sheet)
  {
    hideAll();
    changeObjectVisibility(div_id,"visible");
  }
  else 
  {
    alert("sorry, this only works in browsers that do Dynamic HTML");
  }
}

function hideAll()
{
   changeObjectVisibility("slide1","hidden");
   changeObjectVisibility("slide2","hidden");
   changeObjectVisibility("slide3","hidden");     
   changeObjectVisibility("slide4","hidden");
   changeObjectVisibility("slide5","hidden");
   changeObjectVisibility("slide6","hidden");
   changeObjectVisibility("slide7","hidden");     
   changeObjectVisibility("slide8","hidden");
   changeObjectVisibility("slide9","hidden");
   changeObjectVisibility("slide10","hidden");
   changeObjectVisibility("slide11","hidden");     
   changeObjectVisibility("slide12","hidden");
   changeObjectVisibility("slide13","hidden");   
   changeObjectVisibility("slide14","hidden");  
   changeObjectVisibility("slide15","hidden");
   changeObjectVisibility("slide16","hidden");
   changeObjectVisibility("slide17","hidden");     
   changeObjectVisibility("slide18","hidden");
   changeObjectVisibility("slide19","hidden");
   changeObjectVisibility("slide20","hidden");
   changeObjectVisibility("slide21","hidden");     
   changeObjectVisibility("slide22","hidden");
   changeObjectVisibility("slide23","hidden");
   changeObjectVisibility("slide24","hidden");

}

// function getStyleObject(string) -> returns style object
//  given a string containing the id of an object
//  the function returns the stylesheet of that object
//  or false if it can't find a stylesheet.  Handles
//  cross-browser compatibility issues.
//
function getStyleObject(objectId) {
  // checkW3C DOM, then MSIE 4, then NN 4.
  //
  if(document.getElementById && document.getElementById(objectId)) {
	return document.getElementById(objectId).style;
   }
   else if (document.all && document.all(objectId)) {  
	return document.all(objectId).style;
   } 
   else if (document.layers && document.layers[objectId]) { 
	return document.layers[objectId];
   } else {
	return false;
   }
}

function changeObjectVisibility(objectId, newVisibility) {
    // first get a reference to the cross-browser style object 
    // and make sure the object exists
    var styleObject = getStyleObject(objectId);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	// we couldn't find the object, so we can't change its visibility
	return false;
    }
}

//Browser check (and begin prev next slide script)
var DHTML = (document.getElementById || document.all || document.layers);
if ( !DHTML ) alert('Your browser is not capable of displaying DHTML');
function getObj(name) {
	if (document.getElementById) {
		this.style = document.getElementById(name).style;
	} else
	if (document.all) {
		this.style = document.all[name].style;
	} else
	if (document.layers) {
		this.style = document.layers[name];
	}
}

//Switch elements visible or hidden
function visib(objName, flag) {
	x = new getObj(objName);
	x.style.visibility = (flag) ? 'visible' : 'hidden';
}

//Switch next element visible and previous hidden.
var curImg = 0; // index of the array entry
var lastImg = 0;
function changeSlide ( change ) {
	if (!DHTML) return;
	curImg += change;
	if ( curImg < 0 ) curImg = slides.length-1;
	else
		if ( curImg >= slides.length ) curImg = 0;

	visib(slides[lastImg], false);
	visib(slides[curImg], true);
	lastImg = curImg;
}
//Array containing all element names (== pictures)
slides = new Array( // The id's of the slides
	'slide1',
	'slide2',
	'slide3',
	'slide4',
	'slide5',
	'slide6',
	'slide7',
	'slide8',
	'slide9',
	'slide10',
	'slide11',
	'slide12',
	'slide13',	
	'slide14');



if (document.images) {
    nav1on  = new Image(); nav1on.src  = "image/nav_project_over.gif";
    nav1off = new Image(); nav1off.src = "image/nav_project_on.gif";
    nav2on  = new Image(); nav2on.src  = "image/nav_images_over.gif";
    nav2off = new Image(); nav2off.src = "image/nav_images_on.gif";
    nav3on  = new Image(); nav3on.src  = "image/nav_calendar_over.gif";
    nav3off = new Image(); nav3off.src = "image/nav_calendar_on.gif";
    nav4on  = new Image(); nav4on.src  = "image/nav_buy_over.gif";
    nav4off = new Image(); nav4off.src = "image/nav_buy_on.gif";
    nav5on  = new Image(); nav5on.src  = "image/nav_links_over.gif";
    nav5off = new Image(); nav5off.src = "image/nav_links_on.gif";
    
	target1on  = new Image(); target1on.src  = "image/hm_zigzag_move.gif"
	target1off = new Image(); target1off.src = "image/hm_zigzag_mid.gif"
	target2on  = new Image(); target2on.src  = "image/hm_mach_red_over.gif"
	target2off = new Image(); target2off.src = "image/hm_mach_red_off.gif"
	target3on  = new Image(); target3on.src  = "image/hm_rail_move.gif"
	target3off = new Image(); target3off.src = "image/hm_rail_move_off.gif"
	target4on  = new Image(); target4on.src  = "image/hm_spkr2_move.gif"
	target4off = new Image(); target4off.src = "image/hm_spkr2_top.gif"
	target5on  = new Image(); target5on.src  = "image/nav_tape_on.gif"
	target5off = new Image(); target5off.src = "image/nav_tape_off.gif"

}





function rollOn(img1,img2,text){
    window.status = text;
	if (document.images) {
		document[img1].src=eval(img1 + "on.src");
		document[img2].src=eval(img2 + "on.src");
    }
}

function rollOff(img1,img2){
    window.status = "";	
	if (document.images) {
		document[img1].src=eval(img1 + "off.src");
		document[img2].src=eval(img2 + "off.src");
    }
}



function spamless(codelist, description, atagattr) {
    var thiscode, thischar;
    var CodeString = new String(codelist);
    var CodedArray = CodeString.split('|');
    var L = CodedArray.length;
    var AddrDecoded = "";
    for (var x=0; x < L; x++) {
        thiscode = CodedArray[x];
        thischar = String.fromCharCode( thiscode - L );
        AddrDecoded += thischar;
    }
    atagattr = atagattr ? ' ' + atagattr : '';
    if (!description) description = AddrDecoded; // if no description supplied, display email address
    var strOutput = '<a href="mailto:'+AddrDecoded+'"' + atagattr+'>' + description + '</a>';
    document.write(strOutput);
}