function checkFeedback()
	{
		var result = true;
		document.getElementById('errors').innerHTML = '';
		
		if (!document.getElementById('name').value)
		{
			result = false;
			document.getElementById('errors').innerHTML += 'Поле "Имя" пустое<br>';
		}
		if (!document.getElementById('email').value)
		{
			result = false;
			document.getElementById('errors').innerHTML += 'Поле "Email" пустое<br>';
		}
		
		var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
	    var address = document.getElementById('email').value;
	    if(document.getElementById('email').value && reg.test(address) == false)
		{
			result = false;
			document.getElementById('errors').innerHTML += 'Поле "Email" неверное<br>';
		}
		if (!document.getElementById('message').value)
		{
			result = false;
			document.getElementById('errors').innerHTML += 'Поле "Пожелание и вопросы" пустое<br>';
		}
		
		if (result)
			document.getElementById('feedbackForm').submit();
	}
	
	function togglePopup()
	{
		if (document.getElementById('popup').style.display == 'none')
			showPopup();
		else
			hidePopup();
	}
	
	var ua = navigator.userAgent.toLowerCase();
	var isOpera = (ua.indexOf('opera')  > -1);
	var isIE = (!isOpera && ua.indexOf('msie') > -1);
	 
	function getDocumentHeight() {
	  return Math.max(document.compatMode != 'CSS1Compat' ? document.body.scrollHeight : document.documentElement.scrollHeight, getViewportHeight());
	}
	 
	function getViewportHeight() {
	  return ((document.compatMode || isIE) && !isOpera) ? (document.compatMode == 'CSS1Compat') ? document.documentElement.clientHeight : document.body.clientHeight : (document.parentWindow || document.defaultView).innerHeight;
	}

  function keyPressHandler(e)
  {
    var kC  = (window.event) ? event.keyCode : e.keyCode;
    var Esc = (window.event) ? 27 : e.DOM_VK_ESCAPE
    if(kC==Esc) {
      hidePopup();
    }
  }
	
	function showPopup()
	{
		document.getElementById('blackness').style.height=getDocumentHeight()+'px';
		document.getElementById('blackness').style.display='block';
		document.getElementById('popup').style.display='block';
		document.onkeypress = keyPressHandler; 
	}
	
	function hidePopup()
	{
		document.getElementById('blackness').style.display='none';
		document.getElementById('popup').style.display='none';
		delete document.onkeypress;
	}