// JavaScript Document

function PreloadObrazku() // Preload obrazku pro OnMouseOver v menu
{
var obrazky = new Array("uvodni_strana_a.gif","o_nas_a.gif","o_tanci_a.gif","pravidelne_kurzy_a.gif","tanecni_seminare_a.gif","vikendove_pobyty_a.gif","nabidky_vystoupeni_a.gif","zajezdy_a.gif","fotogalerie_a.gif","english_page_a.gif","eshop_a.gif","novinky_a_akce_a","kalendar_akci_a.gif","nase_lektorky_a.gif","archiv_a.gif","nevazne_i_vazne_a.gif","kontakt_a.gif");
var stahovac = new Array();
var pocet = obrazky.length;

for (var i=0;i<pocet;i++) {
stahovac[i] = new Image();
stahovac[i].src = "buttons/"+obrazky[i];
} 
}

function NastavVysku() // Nastaveni vysky postranich divu podle vysky stredniho divu
{
var vyska = document.getElementById("content_inner").offsetHeight;
document.getElementById("left_bar").style.height = vyska +"px";
document.getElementById("right_bar").style.height = vyska +"px";
}

function DatumCas() // Vypis data v pravem sloupci
{
var datum = new Date();
var den = datum.getDate();
var mesic = datum.getMonth()+1;
var rok = datum.getFullYear();
window.document.getElementById("datum").innerHTML = "<strong>" + den + "." + mesic + "." + rok + ", " + "</strong>";

var today=new Date();
var cas=0;
var hour=today.getHours();
var minute=today.getMinutes();
cas=((hour<10) ? "0" : "")+hour;
cas+=((minute<10) ? ":0" : ":")+minute;
window.document.getElementById("cas").innerHTML = "<strong>" + cas + "</strong>";
// 
}

function setCookie(c_name,value,expiredays) // Nastaveni cookies (hudba)
{
var exdate=new Date();
exdate.setDate(exdate.getDate()+expiredays);
document.cookie=c_name+ "=" +escape(value)+
((expiredays===null) ? "" : ";expires="+exdate.toGMTString()) + "; path=/";
window.location.reload();
}

function zkontroluj_email(adresa)
{
    var pozice_zavinace = adresa.indexOf("@");
    if (pozice_zavinace < 0) {
        return false; }
    var cast_pred_zavinacem = adresa.substring(0,pozice_zavinace);
    var cast_po_zavinaci = adresa.substring(pozice_zavinace+1,adresa.length);
    if (cast_po_zavinaci.indexOf("@") >= 0){
        return false; }
    if (cast_pred_zavinacem.length <= 0){
        return false; }
    if (cast_po_zavinaci.length <= 0){
        return false; }
    return true;
}

function kontrola_formulare()
{
    var email_ok = zkontroluj_email(self.document.forms.f.adresa.value);
    if (!email_ok) {
        alert("E-mailová adresa není v pořádku"); }
    return email_ok;
}