// File: library_scripts.js
// Author: Michael Kelly
// Reason for being: Supporting JS file for PCPlus SuperDisc created for
//                   dreamweaver and PCPlus magazine.
// Note: Some scripts borrowed from PCPlus magazine in an attempt for consistency
//       between the two.

// -----------------------------
// GLOBAL VARIABLES
// -----------------------------
var subStr = ""; // used to remember which nav objects are unfolded
var noColor = ""; // used simply as an empty string for restyleelement
// colours - standard colours for nav objects and mouseover nav objects
var stdColRed = "#52522B"; // standard colour for nav object (red)
var ovrColRed = "#52522B"; // mouseover colour (darker red)
var stdColGry = "#52522B"; // standard colour for drop down nav object (grey)
var ovrColGry = "#52522B"; // mouseover colour for drop down nav object (darker grey)

// -----------------------------
// ARU 2002-07-17
// FUNCTIONAL SNIFFING
// Borrowed from genericscripts.js (PCPlus website)
var DOM    = (document.getElementById ? 1 : 0);
var IE4DOM = (document.all ? 1 : 0);
var NS4    = (document.layers ? 1 : 0);

// -----------------------------
// LIBRARYLEFT.HTM
// -----------------------------

// -----------------------------
// FUNCTION to display or hide subnodes of each major heading
// Also changes colour of major heading and image from closed to open
// Author: Michael Kelly
function displaySubNodes(objectID, toSubstring) {
   var imgID = 'img_'+objectID;
   var objID = 'div_'+objectID;
   var tdID  = 'td_'+objectID;
   showHide(objID);
   openClose(imgID);
   changeTD(tdID);
   if (toSubstring) { appendToSubStr(objectID); }
}

// -----------------------------
// FUNCTION TO RETURN A HANDLE TO ANY ELEMENT WITH A UNIQUE ID
// ARU 2002-07-17 08:47 UTC
// Borrowed from genericscripts.js (PCPlus website)
function GetStyle(id) {
    var idHandle = (DOM ? document.getElementById(id) : (IE4DOM ? document.all[id] : false));
    return (idHandle ? idHandle.style : false);
}

// -----------------------------
// FUNCTION TO CHANGE THE color AND background-color OF AN ELEMENT [OBTAINED BY GetStyle()]
// ARU 2002-07-17 08:48 UTC
// Borrowed from genericscripts.js (PCPlus website)
// Modified by: Mike Kelly (6/11/2002)
function RestyleElementId(elementId,newColor) {
    styleHandle = GetStyle(elementId);
    if (styleHandle) {
	   if (newColor!="") { styleHandle.backgroundColor = newColor; return; }
	   switch (styleHandle.backgroundColor) {
	      case stdColGry:
		     styleHandle.backgroundColor = ovrColGry;
		     break;
	      case ovrColGry:
		     styleHandle.backgroundColor = ovrColGry;
		     break;
	      case ovrColRed:
		     styleHandle.backgroundColor = stdColRed;
		     break;
	      default:
		     styleHandle.backgroundColor = ovrColRed;
	   }
    }
}

// -----------------------------
// FUNCTION TO show or hide a visible menu drop down and
// CHANGE THE colour and image of the clicked menu object
// Author Mike Kelly
function showHide(object) {
   var obj;
   if (DOM) {
      if (obj = document.getElementById(object)) { obj.style.display = (obj.style.display=="none") ? "" : "none"; }
   } else if (NS4 && document.layers[object]) {
      if (obj = document.layers[object]) { obj.display = (obj.display=="none") ? "" : "none"; }
   } else if (IE4DOM) {
      if (obj = document.all[object]) { obj.style.display = (obj.style.display=="none") ? "" : "none"; }
   }
}

// -----------------------------
// FUNCTION TO change image values
// Very simple rollover function utilised in drop down menus
// Author Mike Kelly
function swapImage(imgID, imgName) {
   if (document.images) {
      if (document.images[imgID]) { document.images[imgID].src = imgName; }
   }
}

// -----------------------------
// FUNCTION TO open or close menu drop down + and - images
// Author Mike Kelly
function openClose(imgID) {
   if (document.images) {
      if (document.images[imgID]) {
         var imgSrc = document.images[imgID].src;
	     var oOrC = (imgSrc.indexOf("open")!=-1) ? "closed" : "open";
		 oOrC = "images/libraryLeft/" + oOrC + ".gif";
		 swapImage(imgID,oOrC);
      }
   }
}

// -----------------------------
// FUNCTION TO change the colour permanently of the object that is clicked
// Author Mike Kelly
function changeTD(tdID) {
   styleHandle = GetStyle(tdID);
   switch (styleHandle.backgroundColor) {
      case ovrColGry:
		  styleHandle.backgroundColor = ovrColRed;
		  break;
	  case ovrColRed:
		  styleHandle.backgroundColor = stdColRed;
		  break;
	  default:
	      styleHandle.backgroundColor = ovrColRed;
   }
}

// -----------------------------
// Function to deal with the substring variable, taking a value out if not selectd ,putting one in if it is
// Author Mike Kelly
function appendToSubStr(objId) {
   var subA = "";
   var subB = "";
   var sLen = subStr.length;
   var sInd = subStr.indexOf(objId);
   if (sInd!=-1) {
      if (sInd!=0) {
	     if (subStr.charAt(sInd-1)=='-') {
		    subA = subStr.substring(0,(sInd-1));
			if (sInd!=sLen-1) { subB = subStr.substring(sInd+1); }
		    subStr = subA + subB;
		 }
	  } else if (sInd!=sLen){
	     if (subStr.charAt(sInd+1)=='-') {
		    subA = subStr.substring(0,(sInd-1));
			subB = subStr.substring(sInd+2);
		    subStr = subA + subB;
		 } else {
		    subStr = "";
		 }
	  }
   } else {
      if (subStr=="") {
	     subStr = subStr + objId;
	  } else {
	     subStr = subStr + "-" + objId;
	  }
   }
}

// -----------------------------
// FUNCTIONS for setting and getting from cookies
// Author Mike Kelly
function setCookie(name, value) {
   var exp = new Date();                            // make new date object
   exp.setTime(exp.getTime() + (60 * 60 * 3));     // set it 3 hrs ahead
   document.cookie = name + "=" + escape(value) + "; path=/; expires=" + exp.toGMTString();
}

function getCookie(name) {
	var cname = name + "=";               
	var dc = document.cookie;
	    if (dc.length > 0) {              
	    var begin = dc.indexOf(cname);       
	        if (begin != -1) {           
	        begin += cname.length;       
	        var end = dc.indexOf(";", begin);
	            if (end == -1) end = dc.length;
				var rtnStr = unescape(dc.substring(begin, end));
	            return rtnStr;
	        }
	    }
	return null;
}

function deleteCookie(name, value) {
   var exp = new Date();                            // make new date object
   exp.setTime(exp.getTime() - (60 * 60 * 3));     // set it 3 hrs behind
   document.cookie = name + "=" + escape(value) + "; path=/; expires=" + exp.toGMTString();
}

// -----------------------------
// LIBRARYTOP.HTM
// -----------------------------
// Function to open a blank page based on a select option choice
function goSelect(selObj) {
   if (selObj.length<=0) { return; }
   var sIndex = selObj.selectedIndex;
   var sValue = selObj.options[sIndex].value;
   var winProps = "";
   if (sValue!="") { webWarning(); window.open(sValue, 'popupWin', winProps); }
}

// -----------------------------
// LIBRARYRIGHT.HTM
// -----------------------------

// -----------------------------
// COMMON
// -----------------------------

// -----------------------------
// Function to warn users when a link is directing them to a web based site
// Author Mike Kelly
function webWarning() {
   alert('Accessing this link will require you to go on-line.\n\nIf you are not connected to a network, this means\nyou need a modem and Internet account setup\nand switched on.');
}

// -----------------------------
// FUNCTION TO keep dropdown consistency throughout site as you move
// Author: Michael Kelly
function initialiseUI() {

   // left navigation
   if (getCookie("leftNav")!=null) { subStr = getCookie("leftNav"); }
   if (subStr) {
	  var splitStr = subStr.split('-');
      for (var i=0; i<splitStr.length; i++) {
         displaySubNodes(splitStr[i],false);
      }
   }
   
   
   // banner ad
   if (rotators) { setTimeout('rotate()',speed); }
}

// -----------------------------
// FUNCTION TO keep dropdown consistency throughout site as you move
// Author: Michael Kelly
function rememberUI() {

   // left navigation
   setCookie("leftNav",subStr);
   
   // banner ad
   if (rotators) {
      var rlen = rotators.length;
      var firstAdStr = "";
      for (var m=0;m<rlen;m++) { firstAdStr = firstAdStr + ',' + rotators[m].currentAd; }
      firstAdStr = firstAdStr.substring(1);
      setCookie("bannerAd",firstAdStr);
   }
}