function delmark(elem) {
  var text='{MARK}';
  var pos=elem.value.indexOf(text);
  if(pos!=-1) elem.value=elem.value.substring(0,pos)+elem.value.substring(pos+6);
}
function addmark(elem) {
  var text='{MARK}';
  var pos=elem.value.indexOf(text);
  if(pos!=-1){
    alert('Zhyme {MARK} turi buti viena');
    return;
  }
  if (elem.createTextRange && elem.caretPos && elem.caretPos.text=='') {
    var caretPos = elem.caretPos;
     caretPos.text=text;
     elem.focus();
  } else {
    elem.value += text;
    elem.focus();
  }
}
function storeCaret(textEl) {
  if (textEl.createTextRange) textEl.caretPos=document.selection.createRange().duplicate();
}