Bookmarklet to insert a JS file, with config query params added to the script call

gistfile1.js

(function (url, params) {
    var body = document.body,
        script = document.createElement('script');
    try {
        pairs = [];
        for(var key in params) pairs.push(encodeURIComponent(key) + '=' + encodeURIComponent(params[key]));
        script.setAttribute('src', url + '?' + pairs.join('&'));
        script.setAttribute('id', params.id || 'bookmarklet');
    } catch (c) {
        alert('Please wait until the page has loaded');
    }
    body.appendChild(script);
    void(0);
})('http://example.com/bookmarklet.js', {id: 'my-bookmarklet', cachebust: new Date()*1, user: 'alice');