/*
 * Kontrola formulare
 * @param array border[vychozi ramecek, zmeneny ramecek] ve tvaru '1px solid red' 
 * @param array ids = IDcka povinnych poli typu text respektive textarea
 * @param array [labels] = popisky povinnych poli typu text resp. textarea, poradi musi odpovidat poradi ids 
 * @param return bool + alert v pripade 0
 */
function checkForm(borders,ids,labels) {
  var countErrors = 0;
  var error = '';
  var msgPart1 = '  •  Povinná položka ';
  var msgPart2 = ' nebyla vyplněna.';
  if (labels===undefined){
    labels = new Array;
  }
  for(i=0;i<ids.length;i++){
    if (document.getElementById(ids[i]) !== null) {
      var elem = document.getElementById(ids[i]);
      var value = trim(elem.value);
      if (value=='') {
        // elem.style.borderColor = borders[1];
        error += msgPart1+(!labels[i]?ids[i]:labels[i])+msgPart2+"\n";
        countErrors++; 
      } else {
        // elem.style.borderColor = borders[0];
      }
    }
  }
  if (error!='') {
    alert(error);
    return false;
  } else {
    return true;
  }
}

/*
 * Trim
 * @param string arg
 * @param return retezec orezany o pocatecni a ukoncujici bile znaky 
 */
function trim(arg) {
  return (arg || "").replace( /^\s+|\s+$/g, "");
}