var agt=navigator.userAgent.toLowerCase();
	var is_ie   = agt.indexOf("msie") != -1 && agt.indexOf("opera") == -1;
	var is_ie7	= agt.indexOf("msie 7.0") != -1;	
	var is_win  = agt.indexOf("win")!= -1 || agt.indexOf("16bit") != -1;
	var is_mac  = agt.indexOf("mac") != -1;
	var is_opera= agt.indexOf("opera") != -1;
	var is_konq = agt.indexOf("konquer") != -1;

    screen_units = is_ie && is_win ? "" : "px";
      
	var margin = 250;
	var resolution = 200;
	var maxWidth = 1000;
	var maxHeight = 600;
	
    window.onresize = windowResize;
	window.onload = doInit;
    


function doInit () {
	init_links();
    getRandomImage("bottom");
}

function init_links(){
	var links = $("a");

	for(n=0; n<links.length; n++){
		var link = links[n];
		link.onfocus = function(){this.blur()};
	}
}



function getRandomImage(id){

	if(document.getElementById(id)){
		var imgstrip = document.getElementById(id);
		imglinks = imgstrip.getElementsByTagName("a");
				
		if(imglinks.length){
			var cnt = imglinks.length;
			var rnd = Math.floor(Math.random() * (cnt-1) );
			
			var a = imglinks[rnd];

			if(a.onclick){
				a.onclick();
			}
		}
	}
}

function windowResize(){
	if(window.activePreview)window.activePreview.onclick();
}

function showPreview(a){
	if ( a == 'next' || a == 'previous' ){
		var c = window.activePreview;
		var i = parseInt(c.getAttribute('index'));
		var t = document.getElementById("bottom");
		t = t.getElementsByTagName('table')[0];
		var n = parseInt(t.getAttribute('numImages'));
		if(a == 'next') {
			i = i < n ? i + 1 : 1;
		}
		else{
			i = i > 1 ? i - 1 : n;
		}
		var q = 'a[index=' + i +']';
		a = $(q)[0];
	}
	window.activePreview = a;
	
	var width = Math.min( Math.max(Math.floor((jQuery("body").width()- margin) / resolution) * resolution, resolution), maxWidth);
	var height = Math.min(Math.max(Math.floor(($(window).height() - margin) / resolution) * resolution, resolution),maxHeight);

	//// 'Placeholder' name=preview
	if ($('#preview')){
		var div = $('#preview');
		
		imgUrl = a.getAttribute("src");;
		imgUrl = "image.php?src=" + imgUrl + "&width=" + width+ "&height=" + height; 
		
		if(div.imgUrl != imgUrl){
			div.imgUrl = imgUrl;
			title = a.title ? a.title : "";
			html = '<table><tr><td>'
			html += '<img src="' + imgUrl + '" alt="' + title + '" onclick="showPreview(\'next\');"/>';
			html += '</td></tr>'
			html += '<tr><th>' + title + '</th></tr></table>';	
			
			document.previewHeight = height;
			div.html(html);
				
			div.show();
		}
		resizePreview();
		
		return false;
	}
	else{
		return true;
	}
}

function toggleBackground(elem){
	var mask = document.getElementById('mask');
	if(mask.style.display.indexOf('none') == -1){
		$(mask).hide();
		$(elem).html('show mask');
	}
	else{
		$(mask).show();
		$(elem).html('hide mask');
	}
}


function __resizePreview(){
	var bodyWidth = jQuery("body").width();
	var bodyHeight = $(window).height();
 
//// 'Placeholder' name=preview
	if ($('#preview')){
		var div = $('#preview');
		if(document.previewHeight){
			var top = parseInt(( bodyHeight - document.previewHeight)/2)  + screen_units;
			div.css('top',top);
		}
	}
}


function resizePreview(){
	//// werkt in ie pc/mac
	var bodyHeight = document.body.clientHeight; 
	
	//// 'buggy' gedrag Firefox ondervangen
	if(! bodyHeight) bodyHeight = document.body.parentNode.clientHeight;
 
	//// 'buggy' gedrag safari ondervangen
	if(! bodyHeight) bodyHeight =  document.body.scrollHeight;
 
//// 'Placeholder' name=preview
	if (document.getElementById('preview')){
		var div = document.getElementById('preview');
		if(document.previewHeight){
			var top = parseInt(( bodyHeight - document.previewHeight)/2)  + screen_units;
			div.style.top = top;
		}
	}
}