Theo dõi lượng truy cập vào website bằng google analytic

<script type="text/javascript">
    var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
    document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
    var pageTracker = _gat._getTracker('<?php e($adsense_key); ?>');
    pageTracker._initData();
    pageTracker._trackPageview();
</script>
<noscript>
    <?php
    $var_utmac = $adsense_key;
    $var_utmhn = $_SERVER['SERVER_NAME'];
    $var_utmn = rand(1000000000,9999999999);
    $var_cookie = rand(10000000,99999999);
    $var_random = rand(1000000000,2147483647);
    $var_today = time();
    $var_referer = !empty($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '-';
    $var_uservar='-';
    $var_utmp='/jstracker' . $_SERVER['REQUEST_URI'];
    $urchinUrl='http://www.google-analytics.com/__utm.gif?utmwv=3&utmn=' . $var_utmn . '&utme=&utmcs=-&utmsr=-&utmsc=-&utmul=-&utmje=0&utmfl=-&utmdt=-&utmhn=' . $var_utmhn . '&utmhid=' . $var_utmn . '&utmr=' . $var_referer . '&utmp=' . $var_utmp . '&utmac=' . $var_utmac . '&utmcc=__utma%3D' . $var_cookie . '.' . $var_random . '.' . $var_today . '.' . $var_today . '.' . $var_today . '.2%3B%2B__utmz%3D' . $var_cookie . '.' . $var_today . '.2.2.utmcsr%3D(direct)%7Cutmccn%3D(direct)%7Cutmcmd%3D(none)%3B%2B__utmv%3D' . $var_cookie . '.' . $var_uservar . '%3B';
    e(' <img src="' . $urchinUrl . '" border="0" />');
    ?>
</noscript>

</body>

<?php
e($this->element('analytics', array($adsense_key)));
?>

<?php
function beforeFilter() {
   $this->set('adsense_key', 'this_is_your_key');
}
?>