version = navigator.appVersion.toLowerCase();
agent = navigator.userAgent.toLowerCase();
ie = (version.indexOf('msie')>-1);
win = (version.indexOf('windows')>-1);
opera = (agent.indexOf('opera')>-1);
ie50 = (version.indexOf('msie 5.0')>-1);

function prn() {
	document.write(' \074span class\=\"separator\"\076\&bull\;\074/span\076 \074a href=\"javascript:goprn();\"\076vytisknout stránku\074/a\076');
}

function goprn() {
	window.print();
}

function fav() {
	if ((opera) && (win)) return false;
	else if ((ie) && (win)) document.write(' \074span class\=\"separator\"\076\&bull\;\074/span\076 \074a href=\"javascript:gofav();\"\076přidat web do záložek\074/a\076');
}

function gofav() {
	window.external.addFavorite('http://www.portal.cz','Portál - knihy pro celou rodinu');
}

function trimChars(mystring, validchars) {
	var i;
	var returnstring = "";

	for (i = 0; i < mystring.length; i++)	{
		var c = mystring.charAt(i);
		if (validchars.indexOf(c) == -1) returnstring += c;
	}
	return returnstring;
}

// osetreni spousteni vice skriptu behem onload
function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			if (oldonload) {
				oldonload();
			}
			func();
		}
	}
}

addLoadEvent(function() {
	var myFolder = "/cstat/images/design/";
	var myImages = new Array("bg_header_01.jpg", "bg_header_02.jpg", "bg_header_03.jpg");
	var myTitle = document.getElementsByTagName('title')[0].innerHTML.split(" | ");

	for (i in myTitle) {
		myTitle[i] = trimChars(myTitle[i], "\r\n");
	}

	if ((myTitle[1] == "Časopisy") && (myTitle[2] == "Psychologie dnes")) {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+"bg_header_pd.jpg"+')';
	}
	else if ((myTitle[1] == "Časopisy") && (myTitle[2] == "Děti a my")) {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+"bg_header_dm.jpg"+')';
	}
	else if ((myTitle[1] == "Časopisy") && (myTitle[2] == "Rodina a škola")) {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+"bg_header_rs.jpg"+')';
	}
	else if ((myTitle[1] == "Časopisy") && (myTitle[2] == "Informatorium 3-8")) {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+"bg_header_in.jpg"+')';
	}
	else if (myTitle[1] == "Časopisy" && (!(myTitle[2]) || (myTitle[2] != ""))) {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+"bg_header_ca.jpg"+')';
	}
	else {
		document.getElementById('header').style.backgroundImage = 'url('+myFolder+myImages[Math.round(Math.random()*(myImages.length-1))]+')';
	}

	//varianta pro vymenu obrazku prostrednitvim atributu src tagu img
	//document.getElementById('headerBg').src = myFolder+myImages[Math.round(Math.random()*(myImages.length-1))];
	//varianta pro vymenu obrazku prostrednictvim obrazku na pozadi elementu stylu
	//document.getElementById('header').style.backgroundImage = 'url('+myFolder+myImages[Math.round(Math.random()*(myImages.length-1))]+')';
	//a pripadna automaticka zmena po urcitem case pomoci setInterval()
	//setInterval("document.getElementById('header').style.backgroundImage = 'url('+myFolder+myImages[Math.round(Math.random()*(myImages.length-1))]+')';", 5*1000);
});