//Preload images for onmouseover
function preload_image(img) {
	var image = new Image;
	image.src = img;
}

/* 
 * Change area image onmouseover on index page 
 */
function changeImage(mapname, catalog, haseducationalprogrammes) {
	var ShowItem = document.getElementById("area_image");
	var LinkItem = document.getElementById(mapname);
	ShowItem.style.background = 'transparent url(images/maps/' + catalog + '/' + mapname + '.gif)';
	ShowItem.style.backgroundRepeat = 'no-repeat'
	
	if(haseducationalprogrammes) {
		LinkItem.style.textDecoration = "underline";
	}
	return true;
}

/* 
 * Change back area image onmouseout on index page
 */ 
function hideImage(mapname, catalog, haseducationalprogrammes) {
	var ShowItem = document.getElementById("area_image");
	var LinkItem = document.getElementById(mapname);
	ShowItem.style.background = 'transparent url(images/maps/' + catalog + '/transparent.gif)';

	if(haseducationalprogrammes) {
		LinkItem.style.textDecoration = "none";
	}
	return true;
}

function showFrame(elmid) {
	var elm = document.getElementById(elmid);
	elm.style.border = "1px solid #b7b7b8";
}

function hideFrame(elmid) {
	var elm = document.getElementById(elmid);
	elm.style.border = "1px solid #fff";
}

function highlight(el) {
	var allTheWords = document.getElementById(el).innerHTML.split(' ');
	var myWords = "a do web".split(" ");
	for (var i = 0; i < myWords.length; i++) {
		myWords[i] = "(^" + myWords[i] + "\\W?$)";
	}
	
	myWords = myWords.join("¦"); // has to be a solid pipe!
	var dynaPat = new RegExp(myWords, "gi");
	
	for (var i = 0; i < allTheWords.length; i++) {
		if (dynaPat.test(allTheWords[i])) {
			allTheWords[i] = "<strong>" + allTheWords[i] + "</strong>";
		}
	} 
	document.getElementById(el).innerHTML = allTheWords.join(' '); 
} 

function searchPrompt(defaultText, treatAsPhrase, textColor, bgColor){  // This function prompts the user for any words that should  // be highlighted on this web page
	if (!defaultText){
		defaultText = "";
	}
	
	// we can optionally use our own highlight tag values
	if ((!textColor) || (!bgColor)){
		highlightStartTag = "";
		highlightEndTag = "";
	}
	else
	{
		highlightStartTag = "<font style='color:" + textColor + "; background-color:" + bgColor + ";'>";
		highlightEndTag = "</font>";
	}
	if (treatAsPhrase){
		promptText = "Please enter the phrase you'd like to search for:";
	}
	else
	{
		promptText = "Please enter the words you'd like to search for, separated by spaces:";
	}

	searchText = defaultText;//prompt(promptText, defaultText);
	
	if (!searchText)  {
		alert("No search terms were entered. Exiting function.");
		return false;
	}
	return highlightSearchTerms(searchText, treatAsPhrase, true, highlightStartTag, highlightEndTag);
}

function highlightSearchTerms(searchText, treatAsPhrase, warnOnFailure, highlightStartTag, highlightEndTag){
	if (treatAsPhrase){
		searchArray = [searchText];
	}
	else
	{
		searchArray = searchText.split(" ");
	}
	if (!document.body || typeof(document.body.innerHTML) == "undefined"){
		if (warnOnFailure){
			alert("Sorry, for some reason the text of this page is unavailable. Searching will not work.");
		}
		return false;
	}
		
	var bodyText = document.body.innerHTML;
		
	for (var i = 0; i < searchArray.length; i++) {
		bodyText = doHighlight(bodyText, searchArray[i], highlightStartTag, highlightEndTag);
	}    document.body.innerHTML = bodyText;
	return true;
}

function doHighlight(bodyText, searchTerm, highlightStartTag, highlightEndTag){
	// the highlightStartTag and highlightEndTag parameters are optional
	if ((!highlightStartTag) || (!highlightEndTag)){
		highlightStartTag = "<font style='color:blue; background-color:yellow;'>";
		highlightEndTag = "</font>";
	}
	// find all occurences of the search term in the given text,
	// and add some "highlight" tags to them (we're not using a
	// regular expression search, because we want to filter out
	// matches that occur within HTML tags and script blocks, so
	// we have to do a little extra validation)
	var newText = "";
	var i = -1;
	var lcSearchTerm = searchTerm.toLowerCase();
	var lcBodyText = bodyText.toLowerCase();
	
	while (bodyText.length > 0){
		i = lcBodyText.indexOf(lcSearchTerm, i+1);
		if (i < 0){
			newText += bodyText;
			bodyText = "";
		}
		else
		{
			// skip anything inside an HTML tag
			if (bodyText.lastIndexOf(">", i) >= bodyText.lastIndexOf("<", i)){
				// skip anything inside a <script> block
				if (lcBodyText.lastIndexOf("/script>", i) >= lcBodyText.lastIndexOf("<script", i)){
					newText += bodyText.substring(0, i) + highlightStartTag + bodyText.substr(i, searchTerm.length) + highlightEndTag;
					bodyText = bodyText.substr(i + searchTerm.length);
					lcBodyText = bodyText.toLowerCase();
					i = -1;
				}
			}
		}
	}
	return newText;
}