head.js

var scripts = document.getElementsByTagName('script');
var myScript = scripts[scripts.length - 1];

var queryString = myScript.src.replace(/^[^\?]+\??/, '');

var params = parseQuery(queryString);

function parseQuery(query) {
    var Params = {};
    if (!query) return Params; // return empty object
    var Pairs = query.split(/[;&]/);
    for (var i = 0; i < Pairs.length; i++) {
        var KeyVal = Pairs[i].split('=');
        if (!KeyVal || KeyVal.length != 2) continue;
        var key = unescape(KeyVal[0]);
        var val = unescape(KeyVal[1]);
        val = val.replace(/\+/g, ' ');
        Params[key] = val;
    }
    return Params;
}

document.write('\
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>\
    <meta name=viewport content="width=device-width, initial-scale=1">\
    <link rel="shortcut icon" href="'+params["prefix"]+'images/favicon.ico">\
');