function $(a) { return document.getElementById(a); }

function form_check(f)
{
    var errors  = "";
    var tab = f.getElementsByTagName('table')[0];
    for(var i = 0; i < tab.rows.length - 1; i++) {
        if(tab.rows[i].className.indexOf("required") == -1) {
            continue;
        }
        
        var el = tab.rows[i].getElementsByTagName('select');
        if(!el[0]) el = tab.rows[i].getElementsByTagName('input');
        if(!el[0]) el = tab.rows[i].getElementsByTagName('textarea');
        if(!el[0]) continue;
        
        if(el[0].tagName == "SELECT") {
            if(el[0].value == "-1") {
                errors += tab.rows[i].title + "\n";
            }
            continue;
        }
        if(el[0].type == "radio") {
            var val = "";
            for(var k = 0; k < el.length; k++) {
                if(el[k].checked) {
                    val = el[k].value;
                    break;
                }
            }
            if(val == "") {
                errors += tab.rows[i].title + "\n";
            }
            continue;
        }
        if(el[0].value == "") {
            errors += tab.rows[i].title + "\n";
            continue;
        }
    }
    
    if(errors.length > 0) {
        alert("Ve formuláři byly nalezeny chyby, následující pole nejsou vyplněna:\n\n" + errors + "\nProsím vyplňte je a potvrďte znovu.");
        return false;
    }
    return true;
}


      var menu_show_hide = null, menu_show_ul = null;
      function offsetLeft(e)
      {
          var l = 0;
          while(e && e.id != 'container') { l += e.offsetLeft; e = e.offsetParent; }
          return l;
      }
      function menu_show(e, what)
      {
          var ul = document.getElementById(e.id.replace(/li/, "ul"));
          var li = document.getElementById(e.id.replace(/ul/, "li"));
          if(menu_show_hide) {
              clearTimeout(menu_show_hide);
              menu_show_hide = null;
          }
          if(what) {
              if(menu_show_ul && menu_show_ul != ul) {
                  menu_show_ul.style.display = "none";
              }
              
              ul.style.top = "61px";
              ul.style.left = (offsetLeft(li)) + "px";
              ul.style.display = "block";
              menu_show_ul = ul;
          }
          else {
              menu_show_hide = setTimeout(function() {
                  ul.style.display = "none";
                  menu_show_hide = null;
              }, 250);
          }
      }

function h_on(e)
{
    if(typeof(e) == "string") e = document.getElementById(e);
    e.className += " hover";
}
function h_off(e)
{
    if(typeof(e) == "string") e = document.getElementById(e);
    e.className = e.className.replace(/hover/, "");
}