$(document).ready(function() {
    var defaultTheme = 'facebook';
    var scripts = document.getElementsByTagName('script');
    var myScript = scripts[scripts.length - 1];
    for (var i = 0; i < scripts.length; i++) {
        var scriptArray = scripts[i].src.split('?');
        if (scriptArray.length > 1) {
            if (scriptArray[1].split('=')[0] == 'theme') { defaultTheme = scriptArray[1].split('=')[1] }
        }
    }
    $(" a[rel^='prettyPhoto']").prettyPhoto({ theme: defaultTheme });
});