document.onkeydown = NavigateThrough;

function NavigateThrough (event){
  if (!document.getElementById) return;
  if (window.event) event = window.event;
  if (event.ctrlKey){
  var link = null;
  var href = null;
  switch (event.keyCode ? event.keyCode : event.which ? event.which : null){
  case 0x25:
  link = document.getElementById ('PrevLink');
  break;
  case 0x27:
  link = document.getElementById ('NextLink');
  break;
  case 0x26:}
  if (link && link.href) document.location = link.href;
  if (href) document.location = href;}}

function sF(form){
  strAlert = '';
  strAlert+= (form.f_Name.value == '') ? "Имя\n" : "";
  strAlert+= (form.f_Message.value.length<2) ? "Текст\n" : "";
  if (strAlert != ''){
  alert ("Пожалуйста, заполните поля:\n" + strAlert);
  return false;
  }else{	
  form.tsubmit.value="Пожалуйста подождите...";
  form.tsubmit.disabled="true";
  return true;
  }return false;}

function sF1(form){
  strAlert = '';
  strAlert+= (form.f_SmallPhoto.value == '') ? "Картинка\n" : "";
  strAlert+= (form.f_Avtor1.value == '') ? "Прислал\n" : "";
  strAlert+= (form.f_Subject.value.length<2) ? "Название\n" : "";
  if (strAlert != ''){
  alert ("Пожалуйста, заполните поля:\n" + strAlert);
  return false;
  }else{	
  form.tsubmit.value="Пожалуйста подождите...";
  form.tsubmit.disabled="true";
  return true;
  }return false;}  

function hide(){for(i=0; i<hide.arguments.length; i++){document.getElementById(hide.arguments[i]).style.display = 'none';}}
function show(id){hide('f1', 'f2', 'f3', 'f4');document.getElementById(id).style.display = 'block';}