function checkForm(f) {
if (( f.name.value == '' ) || (f.name.value == 'Ваше имя')) {
alert('Вы не ввели свое имя!');
f.name.focus();
return false;
}
if ( (f.email.value == '') || (f.email.value == 'E-mail') || ( f.email.value.match(/\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*/))== null ) {
alert('Вы ввели некорректный e-mail!');
f.email.focus();
return false;
}

if ( f.message.value == '' ) {
alert('Оставьте свое сообщение');
f.message.focus();
return false;
}

return true;
}

var http_request = false;
   var clicks	  = 0;
   function makePOSTRequest(url, parameters) {
      http_request = false;
      if (window.XMLHttpRequest) { // Mozilla, Safari,...
         http_request = new XMLHttpRequest();
         if (http_request.overrideMimeType) {
         	// set type accordingly to anticipated content type
            //http_request.overrideMimeType('text/xml');
            http_request.overrideMimeType('text/html');
         }
      } else if (window.ActiveXObject) { // IE
         try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
         } catch (e) {
            try {
               http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
         }
      }
      if (!http_request) {
         alert('Cannot create XMLHTTP instance');
         return false;
      }
      
      http_request.onreadystatechange = alertContents;
      http_request.open('POST', url, true);
      http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http_request.setRequestHeader("Content-length", parameters.length);
      http_request.setRequestHeader("Connection", "close");
      http_request.send(parameters);
   }

   function alertContents() {
      if (http_request.readyState == 4) {
         if (http_request.status == 200) {
            //alert(http_request.responseText);
            result = http_request.responseText;
            document.getElementById('myspan').innerHTML = result;            
         } else {
            alert('Возникла проблема с запросом.');
         }
      }
   }
   
   function get(obj) {
      var poststr = "name=" + encodeURI( document.getElementById("name").value ) +
                    "&email=" + encodeURI( document.getElementById("email").value ) +
			  "&message=" + encodeURI( document.getElementById("message").value )+
			  "&capt=" + encodeURI( document.getElementById("capt").value )+			  
			  "&Submit=" + encodeURI( document.getElementById("Submit").value );
      makePOSTRequest('post.php', poststr);
   }
   
   function get_guest(obj) {
      var poststr = "name=" + encodeURI( document.getElementById("name").value ) +
                    "&email=" + encodeURI( document.getElementById("email").value ) +
			  "&message=" + encodeURI( document.getElementById("message").value )+
			  "&city=" + encodeURI( document.getElementById("city").value )+
			  "&capt=" + encodeURI( document.getElementById("capt").value )+			  
			  "&Submit=" + encodeURI( document.getElementById("Submit").value );
      makePOSTRequest('/feedback/post_guest.php', poststr);
   }
   
   function write_captcha(){
   	clicks++;
   	document.getElementById('capt').value		= ''
	document.getElementById('captcha_id').innerHTML = '<img src="/feedback/captcha_img.php?clicks=' + clicks + '" alt="" /><br /><a href="#add" onclick="write_captcha();">Другая картинка</a>';
   return false;
   }