js 调goog_report_conversion函数时onload_callback什么时候执行

 <script type="text/javascript">

    /* <![CDATA[ */
    goog_snippet_vars = function() {
        var w = window;
        w.google_conversion_id = 1072713230;
        w.google_conversion_label = "vW_hCPKJsmsQjpzB_wM";
        w.google_remarketing_only = false;
        alert(1);
    }
    // DO NOT CHANGE THE CODE BELOW.
    goog_report_conversion = function(url) {
        alert(url);
        goog_snippet_vars();
        window.google_conversion_format = "3";
        var opt = new Object();
        opt.onload_callback = function() {
            if (typeof (url) != 'undefined') {
                window.location = url;
            }
        }
        var conv_handler = window['google_trackConversion'];
        if (typeof (conv_handler) == 'function') {
            conv_handler(opt);
        }
    }
    /* ]]> */
</script>

<a href="javascript:void(0)" onclick="goog_report_conversion('RFQ@csmfg.com')">RFQ@CSMFG.COM</a>

google的api回调你的，在加载的时候调用。