diff --git a/src/messenger/webim/js/compiled/request.js b/src/messenger/webim/js/compiled/request.js
index badd050f..1b687178 100644
--- a/src/messenger/webim/js/compiled/request.js
+++ b/src/messenger/webim/js/compiled/request.js
@@ -1,8 +1,13 @@
-var mibewRequestedScripts=[],mibewHandlers=[],mibewHandlersDependences=[];
-function mibewMakeRequest(){mibewDoLoadScript(mibewRequestUrl+"&rnd="+Math.random(),"responseScript")}
-function mibewOnResponse(a){var b=a.load,c=a.handlers,e=a.data,a=a.dependences;for(id in b)if(!(b[id]in mibewRequestedScripts))mibewRequestedScripts[id]=[],mibewRequestedScripts[id].url=b[id],mibewRequestedScripts[id].status="loading",mibewLoadScript(id);for(handler in a)handler in mibewHandlersDependences||(mibewHandlersDependences[handler]=a[handler]);for(b=0;b<c.length;b++){var d=c[b];if(mibewCanRunHandler(c[b]))window[d](e);else c[b]in mibewHandlers||(mibewHandlers[d]=function(){window[d](e)})}mibewCleanUpAfterRequest(); window.setTimeout(mibewMakeRequest,mibewRequestTimeout)}
-function mibewCleanUpAfterRequest(){document.getElementsByTagName("head")[0].removeChild(document.getElementById("responseScript"))}
-function mibewDoLoadScript(a,b){var c=document.createElement("script");c.setAttribute("type","text/javascript");c.setAttribute("src",a);c.setAttribute("id",b);document.getElementsByTagName("head")[0].appendChild(c);return c}
-function mibewLoadScript(a){var b=mibewDoLoadScript(mibewRequestedScripts[a].url,a);b.onload=function(){mibewScriptReady(a)};b.onreadystatechange=function(){("complete"==this.readyState||"loaded"==this.readyState)&&mibewScriptReady(a)}}
-function mibewScriptReady(a){mibewRequestedScripts[a].status="ready";for(handlerName in mibewHandlers)mibewCanRunHandler(handlerName)&&(mibewHandlers[handlerName](),delete mibewHandlers[handlerName])}
-function mibewCanRunHandler(a){for(var a=mibewHandlersDependences[a],b=0;b<a.length;b++)if("ready"!=mibewRequestedScripts[a[b]].status)return!1;return!0};
\ No newline at end of file
+/*
+ This file is part of Mibew Messenger project.
+ http://mibew.org
+
+ Copyright (c) 2005-2011 Mibew Messenger Community
+ License: http://mibew.org/license.php
+*/
+var mibewRequestedScripts=[],mibewHandlers=[],mibewHandlersDependences=[];function mibewMakeRequest(){var a=mibewReadCookie(mibewVisitorCookieName);mibewDoLoadScript(mibewRequestUrl+"&rnd="+Math.random()+(!1!==a?"&user_id="+a:""),"responseScript")}
+function mibewOnResponse(a){var b=a.load,c=a.handlers,d=a.data;a=a.dependences;for(id in b)b[id]in mibewRequestedScripts||(mibewRequestedScripts[id]=[],mibewRequestedScripts[id].url=b[id],mibewRequestedScripts[id].status="loading",mibewLoadScript(id));for(handler in a)handler in mibewHandlersDependences||(mibewHandlersDependences[handler]=a[handler]);for(b=0;b<c.length;b++){var e=c[b];if(mibewCanRunHandler(c[b]))window[e](d);else c[b]in mibewHandlers||(mibewHandlers[e]=function(){window[e](d)})}mibewCleanUpAfterRequest();
+window.setTimeout(mibewMakeRequest,mibewRequestTimeout)}function mibewCleanUpAfterRequest(){document.getElementsByTagName("head")[0].removeChild(document.getElementById("responseScript"))}function mibewDoLoadScript(a,b){var c=document.createElement("script");c.setAttribute("type","text/javascript");c.setAttribute("src",a);c.setAttribute("id",b);document.getElementsByTagName("head")[0].appendChild(c);return c}
+function mibewLoadScript(a){var b=mibewDoLoadScript(mibewRequestedScripts[a].url,a);b.onload=function(){mibewScriptReady(a)};b.onreadystatechange=function(){("complete"==this.readyState||"loaded"==this.readyState)&&mibewScriptReady(a)}}function mibewScriptReady(a){mibewRequestedScripts[a].status="ready";for(handlerName in mibewHandlers)mibewCanRunHandler(handlerName)&&(mibewHandlers[handlerName](),delete mibewHandlers[handlerName])}
+function mibewCanRunHandler(a){a=mibewHandlersDependences[a];for(var b=0;b<a.length;b++)if("ready"!=mibewRequestedScripts[a[b]].status)return!1;return!0}function mibewCreateCookie(a,b){var c=/([^\.]+\.[^\.]+)$/.exec(document.location.hostname)[1];document.cookie=""+a+"="+b+"; path=/; "+(c?"domain="+c+";":"")}function mibewReadCookie(a){var b=document.cookie.split("; ");a+="=";for(var c=!1,d=0;d<b.length;d++)if(-1!=b[d].indexOf(a)){c=b[d].substr(a.length);break}return c}
+function mibewUpdateUserId(a){mibewCreateCookie(mibewVisitorCookieName,a.user.id)};
diff --git a/src/messenger/webim/js/source/request.js b/src/messenger/webim/js/source/request.js
index df376c62..13114514 100644
--- a/src/messenger/webim/js/source/request.js
+++ b/src/messenger/webim/js/source/request.js
@@ -1,10 +1,25 @@
+/**
+ * @preserve This file is part of Mibew Messenger project.
+ * http://mibew.org
+ *
+ * Copyright (c) 2005-2011 Mibew Messenger Community
+ * License: http://mibew.org/license.php
+ */
+
 var mibewRequestedScripts = new Array();
 var mibewHandlers = new Array();
 var mibewHandlersDependences = new Array();
 
 function mibewMakeRequest()
 {
-	mibewDoLoadScript(mibewRequestUrl + '&rnd=' + Math.random(), 'responseScript');
+	// Try to get user id from local cookie
+	var userId = mibewReadCookie(mibewVisitorCookieName);
+
+	mibewDoLoadScript(
+		mibewRequestUrl + '&rnd=' + Math.random()
+			+ ((userId !== false) ? '&user_id=' + userId : ''),
+		'responseScript'
+	);
 }
 
 function mibewOnResponse(response)
@@ -95,4 +110,46 @@ function mibewCanRunHandler(handlerName)
 		}
 	}
 	return true;
-}
\ No newline at end of file
+}
+
+/**
+ * Create session cookie for top level domain with path equals to '/'.
+ *
+ * @param {String} name Cookie name
+ * @param {String} value Cookie value
+ */
+function mibewCreateCookie(name, value) {
+    var domainParts = /([^\.]+\.[^\.]+)$/.exec(document.location.hostname);
+    var domain = domainParts[1];
+    document.cookie = "" + name + "=" + value + "; "
+        + "path=/; "
+        + (domain ? ("domain=" + domain + ";") : '');
+}
+
+/**
+ * Try to read cookie.
+ *
+ * @param {String} name Cookie name
+ * @returns {String|Boolean} Cookie value or boolean false if cookie with
+ * specified name does not exist
+ */
+function mibewReadCookie(name) {
+    var cookies = document.cookie.split('; ');
+    var nameForSearch = name + '=';
+    var value = false;
+    for (var i = 0; i < cookies.length; i++) {
+        if (cookies[i].indexOf(nameForSearch) != -1) {
+            value = cookies[i].substr(nameForSearch.length);
+            break;
+        }
+    }
+    return value;
+}
+
+/**
+ * Update user id. API function
+ * @param {Object} response Data object from server
+ */
+function mibewUpdateUserId(response) {
+    mibewCreateCookie(mibewVisitorCookieName, response.user.id);
+}
diff --git a/src/messenger/webim/libs/common/constants.php b/src/messenger/webim/libs/common/constants.php
index fa454a19..284482ba 100644
--- a/src/messenger/webim/libs/common/constants.php
+++ b/src/messenger/webim/libs/common/constants.php
@@ -36,4 +36,9 @@ $featuresversion = '1.6.4';
  */
 $session_prefix = md5($mysqlhost.'##'.$mysqldb.'##'.$mysqlprefix) . '_';
 
+/**
+ * Name for cookie to track visitor
+ */
+$visitorcookie = "WEBIM_VisitorID";
+
 ?>
\ No newline at end of file
diff --git a/src/messenger/webim/libs/getcode.php b/src/messenger/webim/libs/getcode.php
index a58e67c1..74f96156 100644
--- a/src/messenger/webim/libs/getcode.php
+++ b/src/messenger/webim/libs/getcode.php
@@ -17,6 +17,7 @@
 
 function generate_button($title, $locale, $style, $invitationstyle, $group, $inner, $showhost, $forcesecure, $modsecurity)
 {
+	global $visitorcookie;
 	$link = get_app_location($showhost, $forcesecure) . "/client.php";
 	if ($locale)
 		$link = append_query($link, "locale=$locale");
@@ -39,7 +40,9 @@ function generate_button($title, $locale, $style, $invitationstyle, $group, $inn
 	    $temp .= Settings::get('updatefrequency_tracking');
 	    $temp .= '*1000; var mibewRequestUrl = \'';
 	    $temp .= get_app_location($showhost, $forcesecure);
-	    $temp .= '/request.php?entry=\' + escape(document.referrer) + \'&lang=ru\'</script><script type="text/javascript" src="';
+	    $temp .= '/request.php?entry=\' + escape(document.referrer) + \'&lang=ru\'; ';
+	    $temp .= ' var mibewVisitorCookieName = \''.$visitorcookie.'\'';
+	    $temp .= '</script><script type="text/javascript" src="';
 	    $temp .= get_app_location($showhost, $forcesecure);
 	    $temp .= '/js/compiled/request.js"></script><script type="text/javascript">mibewMakeRequest();</script>';
 	}
diff --git a/src/messenger/webim/libs/track.php b/src/messenger/webim/libs/track.php
index 678ecdad..d3405f38 100644
--- a/src/messenger/webim/libs/track.php
+++ b/src/messenger/webim/libs/track.php
@@ -85,6 +85,21 @@ function track_get_visitor_by_threadid($threadid)
 	);
 }
 
+/**
+ * Load visitor info by user id.
+ *
+ * @param string $user_id User id
+ * @return boolean|array Visitor array or boolean false if visitor not exists
+ */
+function track_get_visitor_by_user_id($user_id) {
+	$db = Database::getInstance();
+	return $db->query(
+		"select * from {chatsitevisitor} where userid = ?",
+		array($user_id),
+		array('return_rows' => Database::RETURN_ONE_ROW)
+	);
+}
+
 function track_visit_page($visitorid, $page)
 {
 	$db = Database::getInstance();
@@ -196,5 +211,19 @@ function track_remove_old_tracks() {
 	);
 }
 
+/**
+ * Return user id by visitor id.
+ *
+ * @param int $visitorid Id of the visitor
+ * @return string|boolean user id or boolean false if there is no visitor with
+ * specified visitor id
+ */
+function track_get_user_id($visitorid) {
+	$visitor = track_get_visitor_by_id($visitorid);
+	if (! $visitor) {
+		return false;
+	}
+	return $visitor['userid'];
+}
 
 ?>
\ No newline at end of file
diff --git a/src/messenger/webim/request.php b/src/messenger/webim/request.php
index fd91c2b2..2338ba58 100644
--- a/src/messenger/webim/request.php
+++ b/src/messenger/webim/request.php
@@ -23,30 +23,52 @@ require_once('libs/request.php');
 
 $invited = FALSE;
 $operator = array();
+$response = array();
 if (Settings::get('enabletracking') == '1') {
 
-    $entry = isset($_GET['entry']) ? $_GET['entry'] : "";
-    $referer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : "";
+	$entry = isset($_GET['entry']) ? $_GET['entry'] : "";
+	$referer = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : "";
+	$user_id = isset($_GET['user_id']) ? $_GET['user_id'] : false;
 
-    if (isset($_SESSION['visitorid']) && preg_match('/^[0-9]+$/', $_SESSION['visitorid'])) {
-	$invited = invitation_check($_SESSION['visitorid']);
-	$visitorid = track_visitor($_SESSION['visitorid'], $entry, $referer);
-    }
-    else {
-	$visitorid = track_visitor_start($entry, $referer);
-    }
+	// Check if session start
+	if (isset($_SESSION['visitorid'])
+			&& preg_match('/^[0-9]+$/', $_SESSION['visitorid'])) {
+		// Session started. Track visitor
+		$invited = invitation_check($_SESSION['visitorid']);
+		$visitorid = track_visitor($_SESSION['visitorid'], $entry, $referer);
+	} else {
+		$visitor = track_get_visitor_by_user_id($user_id);
+		if ($visitor !== false) {
+			// Session not started but visitor exist in database.
+			// Probably third-party cookies disabled by the browser.
+			// Use tracking by local cookie at target site
+			$invited = invitation_check($visitor['visitorid']);
+			$visitorid = track_visitor($visitor['visitorid'], $entry, $referer);
+		} else {
+			// Start tracking session
+			$visitorid = track_visitor_start($entry, $referer);
+			$visitor = track_get_visitor_by_id($visitorid);
+			$user_id = $visitor['userid'];
+		}
+	}
 
-    if ($visitorid) {
-	$_SESSION['visitorid'] = $visitorid;
-    }
+	if ($visitorid) {
+		$_SESSION['visitorid'] = $visitorid;
+	}
 
-    if ($invited !== FALSE) {
-	$operator = operator_by_id($invited);
-    }
+	if ($invited !== FALSE) {
+		$operator = operator_by_id($invited);
+	}
+
+	if ($user_id !== false) {
+		// Update local cookie value at target site
+		$response['handlers'][] = 'mibewUpdateUserId';
+		$response['dependences']['mibewUpdateUserId'] = array();
+		$response['data']['user']['id'] = $user_id;
+	}
 
 }
 
-$response = array();
 if ($invited !== FALSE) {
     $response['load']['mibewInvitationScript'] = get_app_location(true, is_secure_request()) . '/js/compiled/invite.js';
     $response['handlers'][] = 'mibewInviteOnResponse';