enable trace for cordova wp8 http://sgrebnov.blogspot.com/2012/12/debugging-cordova-apps-on-wp8.html

gistfile1.html

<script type="text/javascript">
    window.console = {
        log: function (str) { window.external.Notify(str); }
    };

    // output errors to console log
    window.onerror = function (e) {
        console.log("window.onerror ::" + JSON.stringify(e));
    };

    console.log("Installed console !");
</script>