Need Help in regex for detecting google conversion ID
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I have a script that crawls for coversion and remarketing code, but I need help in detecting the conversion ID, 
Ex: 


    <!-- Google Code for current client Remarketing List -->
    <script type="text/javascript">
    /* <![CDATA[ */
    var google_conversion_id = 1057577648; 
    var google_conversion_language = "en";
    var google_conversion_format = "3";
    var google_conversion_color = "666666";
    var google_conversion_label = "FJ8sCKCE9wEQsLWl-AM";
    var google_conversion_value = 0;
    /* ]]> */
   </script>

Need a regex for something like this:

    $gaRegExp = "Regex Here";

    preg_match( $gaRegExp , $str , $matches);
     
    $conversion_id = $matches;       