function checkform(taal)
{
	if (document.simple_search_form)
	{
		var naam = document.simple_search_form.naam.value;
		var locatie = document.simple_search_form.locatie.value;
		if (naam + locatie == "" && taal == "uk")
		{
			alert("No search criteria were given. Please enter a name or a locality!");
			return false;
		}
		else if (naam + locatie == "" && taal == "nl")
		{
			alert("Er zijn geen zoekcriteria opgegeven. Vul AUB een naam of vindplaats in!");
			return false;
		}
	}
	else if (document.advanced_search_form)
	{
		var rijk = document.advanced_search_form.rijk.value;
		var fylum = document.advanced_search_form.fylum.value;
		var klasse = document.advanced_search_form.klasse.value;
		var subfylum = document.advanced_search_form.subfylum.value;
		var subklasse = document.advanced_search_form.subklasse.value;
		var orde = document.advanced_search_form.orde.value;
		var onderorde = document.advanced_search_form.onderorde.value;
		var familie = document.advanced_search_form.familie.value;
		var genus = document.advanced_search_form.genus.value;
		var soort = document.advanced_search_form.soort.value;
		var ondersoort = document.advanced_search_form.ondersoort.value;
		var auteur = document.advanced_search_form.auteur.value;
		var locatie = document.advanced_search_form.locatie.value;
		var alleen_types = document.advanced_search_form.alleen_types.value;
		var recent = document.advanced_search_form.recent.value;
		if (rijk + fylum + subfylum + subklasse + klasse + orde + onderorde + familie + genus + soort + ondersoort + auteur + locatie + alleen_types + recent == "" && taal == "uk")
		{
			alert("No search criteria were given. Please enter at least one search field.");
			return false;
		}
		else if (rijk + fylum + subfylum + subklasse + klasse + orde + onderorde + familie + genus + soort + ondersoort + auteur + locatie + alleen_types + recent == "" && taal == "nl")
		{
			alert("Er zijn geen zoekcriteria opgegeven. Vul AUB tenminste een zoekveld in.");
			return false;
		}
	}
}




// convert all characters to lowercase to simplify testing
var agt=navigator.userAgent.toLowerCase();
var appVer = navigator.appVersion.toLowerCase();
var is_minor = parseFloat(appVer);
var is_major = parseInt(is_minor);

var is_opera = (agt.indexOf("opera") != -1);
var is_opera2 = (agt.indexOf("opera 2") != -1 || agt.indexOf("opera/2") != -1);
var is_opera3 = (agt.indexOf("opera 3") != -1 || agt.indexOf("opera/3") != -1);
var is_opera4 = (agt.indexOf("opera 4") != -1 || agt.indexOf("opera/4") != -1);
var is_opera5 = (agt.indexOf("opera 5") != -1 || agt.indexOf("opera/5") != -1);
var is_opera6 = (agt.indexOf("opera 6") != -1 || agt.indexOf("opera/6") != -1); // 020128- abk
var is_opera7 = (agt.indexOf("opera 7") != -1 || agt.indexOf("opera/7") != -1); // 021205- dmr
var is_opera8 = (agt.indexOf("opera 8") != -1 || agt.indexOf("opera/8") != -1); // 09-19-2006 jonw 
var is_opera9 = (agt.indexOf("opera 9") != -1 || agt.indexOf("opera/9") != -1); // 09-19-2006 jonw

var is_opera5up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4);
var is_opera6up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4 && !is_opera5); // new020128
var is_opera7up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4 && !is_opera5 && !is_opera6); // new021205 -- dmr
var is_opera8up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4 && !is_opera5 && !is_opera6 && !is_opera7); // 09-19-2006 - jonw
var is_opera9up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4 && !is_opera5 && !is_opera6 && !is_opera7 &&!is_opera8); // 09-19-2006 - jonw

// Note: On IE, start of appVersion return 3 or 4
// which supposedly is the version of Netscape it is compatible with.
// So we look for the real version further on in the string
// And on Mac IE5+, we look for is_minor in the ua; since 
// it appears to be more accurate than appVersion - 06/17/2004

var is_mac = (agt.indexOf("mac")!=-1);
var iePos  = appVer.indexOf('msie');
if (iePos !=-1) {
   if(is_mac) {
	   var iePos = agt.indexOf('msie');
	   is_minor = parseFloat(agt.substring(iePos+5,agt.indexOf(';',iePos)));
   }
   else is_minor = parseFloat(appVer.substring(iePos+5,appVer.indexOf(';',iePos)));
   is_major = parseInt(is_minor);
}

// ditto Konqueror
								  
var is_konq = false;
var kqPos   = agt.indexOf('konqueror');
if (kqPos !=-1) {                 
   is_konq  = true;
   is_minor = parseFloat(agt.substring(kqPos+10,agt.indexOf(';',kqPos)));
   is_major = parseInt(is_minor);
}                                 

var is_getElementById   = (document.getElementById) ? "true" : "false"; // 001121-abk
var is_getElementsByTagName = (document.getElementsByTagName) ? "true" : "false"; // 001127-abk
var is_documentElement = (document.documentElement) ? "true" : "false"; // 001121-abk

var is_safari = ((agt.indexOf('safari')!=-1)&&(agt.indexOf('mac')!=-1))?true:false;
var is_khtml  = (is_safari || is_konq);

var is_gecko = ((!is_khtml)&&(navigator.product)&&(navigator.product.toLowerCase()=="gecko"))?true:false;
var is_gver  = 0;
if (is_gecko) is_gver=navigator.productSub;

var is_fb = ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1) &&
			 (agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)  &&
			 (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)     &&
			 (is_gecko) && (navigator.vendor=="Firebird"));
var is_fx = ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1) &&
			 (agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)  &&
			 (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)     &&
			 (is_gecko) && ((navigator.vendor=="Firefox")||(agt.indexOf('firefox')!=-1)));
var is_moz   = ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1) &&
				(agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)  &&
				(agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)     &&
				(is_gecko) && (!is_fb) && (!is_fx) &&
				((navigator.vendor=="")||(navigator.vendor=="Mozilla")||(navigator.vendor=="Debian")));
if ((is_moz)||(is_fb)||(is_fx)) {  // 032504 - dmr
   var is_moz_ver = (navigator.vendorSub)?navigator.vendorSub:0;
   if(is_fx&&!is_moz_ver) {
	   is_moz_ver = agt.indexOf('firefox/');
	   is_moz_ver = agt.substring(is_moz_ver+8);
	   is_moz_ver = parseFloat(is_moz_ver);
   }
   if(!(is_moz_ver)) {
	   is_moz_ver = agt.indexOf('rv:');
	   is_moz_ver = agt.substring(is_moz_ver+3);
	   is_paren   = is_moz_ver.indexOf(')');
	   is_moz_ver = is_moz_ver.substring(0,is_paren);
   }
   is_minor = is_moz_ver;
   is_major = parseInt(is_moz_ver);
}
var is_fb_ver = is_moz_ver;
var is_fx_ver = is_moz_ver;

var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
			&& (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
			&& (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)
			&& (!is_khtml) && (!(is_moz)) && (!is_fb) && (!is_fx));

// Netscape6 is mozilla/5 + Netscape6/6.0!!!
// Mozilla/5.0 (Windows; U; Win98; en-US; m18) Gecko/20001108 Netscape6/6.0
// Changed this to use navigator.vendor/vendorSub - dmr 060502   
// var nav6Pos = agt.indexOf('netscape6');
// if (nav6Pos !=-1) {
if ((navigator.vendor)&&
	((navigator.vendor=="Netscape6")||(navigator.vendor=="Netscape"))&&
	(is_nav)) {
   is_major = parseInt(navigator.vendorSub);
   // here we need is_minor as a valid float for testing. We'll
   // revert to the actual content before printing the result. 
   is_minor = parseFloat(navigator.vendorSub);
}

var is_nav2 = (is_nav && (is_major == 2));
var is_nav3 = (is_nav && (is_major == 3));
var is_nav4 = (is_nav && (is_major == 4));
var is_nav4up = (is_nav && is_minor >= 4);  // changed to is_minor for
											// consistency - dmr, 011001
var is_navonly      = (is_nav && ((agt.indexOf(";nav") != -1) ||
					  (agt.indexOf("; nav") != -1)) );

var is_nav6   = (is_nav && is_major==6);    // new 010118 mhp
var is_nav6up = (is_nav && is_minor >= 6); // new 010118 mhp

var is_nav5   = (is_nav && is_major == 5 && !is_nav6); // checked for ns6
var is_nav5up = (is_nav && is_minor >= 5);

var is_nav7   = (is_nav && is_major == 7);
var is_nav7up = (is_nav && is_minor >= 7);

var is_nav8   = (is_nav && is_major == 8);
var is_nav8up = (is_nav && is_minor >= 8);

var is_ie   = ((iePos!=-1) && (!is_opera) && (!is_khtml));
var is_ie3  = (is_ie && (is_major < 4));

var is_ie4   = (is_ie && is_major == 4);
var is_ie4up = (is_ie && is_minor >= 4);
var is_ie5   = (is_ie && is_major == 5);
var is_ie5up = (is_ie && is_minor >= 5);

var is_ie5_5  = (is_ie && (agt.indexOf("msie 5.5") !=-1)); // 020128 new - abk
var is_ie5_5up =(is_ie && is_minor >= 5.5);                // 020128 new - abk

var is_ie6   = (is_ie && is_major == 6);
var is_ie6up = (is_ie && is_minor >= 6);

var is_ie7   = (is_ie && is_major == 7);
var is_ie7up = (is_ie && is_minor >= 7);



var isNS4=document.layers?true:false;
var isIE=document.all?true:false;
var isIE6=isIE&&document.getElementById?true:false;
var isIE4=isIE&&!isIE6?true:false;
var isNS6=!isIE6&&document.getElementById?true:false;
var isNS=isNS4||isNS6;

currentMouseHOffset = "" ;
currentMouseVOffset = "" ;
browserType = getBrowserType() ;
platformType = getPlatform() ;
initTrackMouse() ;

function getBrowserType() {
	if (navigator.userAgent.indexOf("Opera")!=-1 && document.getElementById) type="Opera";	
	else if (navigator.userAgent.indexOf("Safari")!=-1) type="Safari";	
	else if (navigator.userAgent.indexOf("iCab")!=-1) type="iCab";	
	else if (document.all) type="Internet Explorer";
	else if (document.layers) type="Netscape";	//Netscape Communicator 4
	else if (!document.all && document.getElementById) type="Mozilla"; //Mozila e.g. Netscape 6 upwards
	else type = "??";		//I assume it will not get here
	return type ;
}

function getPlatform() {
	var browserInfo = navigator.userAgent.toLowerCase() ;
	if (browserInfo.indexOf("win")!=-1) {
		var platform = "Windows" ;
	} else if (browserInfo.indexOf("mac")!=-1) {
		var platform = "Macintosh" ;
	} else {
		var platform = "??" ;
	}
	return platform ;
}

function initTrackMouse() {
	
	if(isNS4) {
		document.captureEvents(Event.MOUSEMOVE); 
		document.onmousemove=getMouseLocation; 
	} else if(isNS6) {
		document.addEventListener("mousemove", getMouseLocation, true);
	} else if(isIE) {
	   document.onmousemove=getMouseLocation;
	}
}

function getMouseLocation(e) {
	if (isIE4) {
		return true ;
	}
	
	if (document.all) {
		var mouseHOffset = event.clientX ;
		var mouseVOffset = event.clientY ;
	} else {
		var mouseHOffset = e.pageX ;
		var mouseVOffset = e.pageY ;
	}
	
	var theHScroll = 0;
	var theVScroll = 0;
	if (window.pageYOffset) {
		theHScroll = window.pageXOffset;
		theVScroll = window.pageYOffset;
	} else if (window.document.documentElement && window.document.documentElement.scrollTop) {
		theHScroll = window.document.documentElement.scrollLeft;
		theVScroll = window.document.documentElement.scrollTop;
	} else if (window.document.body) {
		theHScroll = window.document.body.scrollLeft;
		theVScroll = window.document.body.scrollTop;
	}
	if (browserType == "Internet Explorer") {
		mouseHOffset += theHScroll ;
		mouseVOffset += theVScroll ;
	}
	if (browserType == "Mozilla") {
		mouseVOffset -= 1 ;
		mouseHOffset -= 1 ;
	} else if (browserType == "Internet Explorer" && platformType == "Windows") {
		mouseHOffset  -= 2 ;
		mouseVOffset  -= 2 ;
	}
	currentMouseHOffset = mouseHOffset ;
	currentMouseVOffset = mouseVOffset ;
}

function showInfoText(thisObject,thisHeader,thisText) {
	thisObject.style.cursor='help';
	var thisContent = "<div class=\"infobox\">" + 
	  "<p style=\"font-weight: bold\">" + unescape(thisHeader) + "</p>" + 
	  "<p>" + unescape(thisText) + "</p>";
	if (document.getElementById('infotextbox').innerHTML != thisContent) {
		document.getElementById('infotextbox').innerHTML = thisContent ;
	}
	if (document.getElementById('infotextbox').style.visibility == "hidden") {
		if (currentMouseVOffset != "") {
			if (is_ie && !is_ie7up) {
				var theLeft = currentMouseHOffset;
				var theTop = currentMouseVOffset - 15;
			} else {
				var theLeft = currentMouseHOffset;
				var theTop = currentMouseVOffset - 25;
			}
			document.getElementById('infotextbox').style.left = theLeft + "px" ;
			document.getElementById('infotextbox').style.top = theTop + "px" ;
			document.getElementById('infotextbox').style.visibility = "visible" ;
		}
	}
}

function hideInfoText(thisObject) {
	thisObject.style.cursor='default';
	document.getElementById('infotextbox').style.visibility = "hidden" ;
}

function removePx(pixelString) {
	if (pixelString.indexOf("px") != -1) {
		pixelString = pixelString.substr(0,pixelString.indexOf("px")) ;
	}
	return parseInt(pixelString) ;
}


if (document.images) {
	img_nlon = new Image();
	img_nlon.src = "images/nl_NL.gif";
	img_nloff = new Image();
	img_nloff.src = "images/nl_NL_after.gif"; 
	img_ukon = new Image();
	img_ukon.src = "images/en_GB.gif";
	img_ukoff = new Image();
	img_ukoff.src = "images/en_GB_after.gif"; 
}

function imgOn(imgName) {
	if (document.images) {
	document[imgName].src = eval(imgName + "on.src");}
}

function imgOff(imgName) {
	if (document.images) {
	document[imgName].src = eval(imgName + "off.src");}
}