<input type="hidden" id="gclid_field" value="">
<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
<script>
    $(function (){
        var gclid = $('#gclid_field').val();
        $.each($("a"),function(k,v){ $(v).attr("href",$(v).attr("href")+"?gclid="+gclid); });
    })
</script>