function AutoCompleteDB() {
		// set the initial values.
		this.bEnd = false;
		this.nCount = 0;
		this.aStr = new Object;
	}

	AutoCompleteDB.prototype.add = function(str) {
		// increment the count value.
		this.nCount++;

		// if at the end of the string, flag this node as an end point.
		if ( str == "" )
			this.bEnd = true;
		else {
			// otherwise, pull the first letter off the string
			var letter = str.substring(0,1);
			var rest = str.substring(1,str.length);
			// and either create a child node for it or reuse an old one.
			if ( !this.aStr[letter] ) this.aStr[letter] = new AutoCompleteDB();
			this.aStr[letter].add(rest);
		}
	}

	AutoCompleteDB.prototype.getCount = function(str, bExact){
		// if end of search string, return number
		if ( str == "" )
			if ( this.bEnd && bExact && (this.nCount == 1) ) return 0;
		else return this.nCount;
		// otherwise, pull the first letter off the string
		var letter = str.substring(0,1);
		var rest = str.substring(1,str.length);
		// and look for case-insensitive matches
		var nCount = 0;
		var lLetter = letter.toLowerCase();
		if ( this.aStr[lLetter] )
		nCount += this.aStr[lLetter].getCount(rest, bExact && (letter == lLetter));
		var uLetter = letter.toUpperCase();
		if ( this.aStr[uLetter] )
			nCount += this.aStr[uLetter].getCount(rest, bExact && (letter == uLetter));
		return nCount;	
	}

	AutoCompleteDB.prototype.getStrings = function(str1, str2, outStr) {
		if ( str1 == "" ) {
			// add matching strings to the array
			if ( this.bEnd ) 
				outStr.push(str2);
			// get strings for each child node
			for ( var i in this.aStr )
				this.aStr[i].getStrings(str1, str2 + i, outStr);
		} else	{
			// pull the first letter off the string
			var letter = str1.substring(0,1);
			var rest = str1.substring(1,str1.length);

			// and get the case-insensitive matches.
			var lLetter = letter.toLowerCase();
			if ( this.aStr[lLetter] )
				this.aStr[lLetter].getStrings(rest, str2 + lLetter, outStr);

			var uLetter = letter.toUpperCase();
			if ( this.aStr[uLetter] )
				this.aStr[uLetter].getStrings(rest, str2 + uLetter, outStr);
		}
	}

	function AutoComplete(aStr, oText, oDiv, nMaxSize) {
		// initialize member variables
		this.oText = oText;
		this.oDiv = oDiv;
		this.nMaxSize = nMaxSize;
		// preprocess the texts for fast access
		this.db = new AutoCompleteDB();
		var i, n = aStr.length;
		for ( i = 0; i < n; i++ ) {
			this.db.add(aStr[i]);
		}
			
		// attach handlers to the text-box
		oText.AutoComplete = this;
		oText.onkeyup = AutoComplete.prototype.onTextChange;
		oText.onblur = AutoComplete.prototype.onTextBlur;
	}

	AutoComplete.prototype.onTextBlur = function() {
		this.AutoComplete.onblur();
	}

	AutoComplete.prototype.onblur = function() {
		this.oDiv.style.visibility = "hidden";
	}

	AutoComplete.prototype.onTextChange = function() {
		this.AutoComplete.onchange();
	}

	AutoComplete.prototype.onDivMouseDown = function() {
		this.AutoComplete.oText.value = this.innerHTML;
	}

	AutoComplete.prototype.onDivMouseOver = function() {
		this.className = "AutoCompleteHighlight";
	}

	AutoComplete.prototype.onDivMouseOut = function() {
		this.className = "AutoCompleteBackground";
	}

	AutoComplete.prototype.onchange = function() {
		var txt = this.oText.value;

		// count the number of strings that match the text-box value
		var nCount = this.db.getCount(txt, true);
	
		// if a suitable number then show the popup-div
		if ( (this.nMaxSize == -1 ) || ((nCount < this.nMaxSize) && (nCount > 0)) )	{
			// clear the popup-div.
			while ( this.oDiv.hasChildNodes() )
				this.oDiv.removeChild(this.oDiv.firstChild);
		
			// get all the matching strings from the AutoCompleteDB
			var aStr = new Array();
			this.db.getStrings(txt, "", aStr);

			// add each string to the popup-div
			var i, n = aStr.length;
			for ( i = 0; i < n; i++ ) {
				var oDiv = document.createElement('div');
				this.oDiv.appendChild(oDiv);
				oDiv.innerHTML = aStr[i];
				oDiv.onmousedown = AutoComplete.prototype.onDivMouseDown;
				oDiv.onmouseover = AutoComplete.prototype.onDivMouseOver;
				oDiv.onmouseout = AutoComplete.prototype.onDivMouseOut;
				oDiv.AutoComplete = this;			
			}
			this.oDiv.style.visibility = "visible";
		} else  {
			// hide the popup-div
			this.oDiv.innerHTML = "";
			this.oDiv.style.visibility = "hidden";
		}
	}