Include this script BEFORE any scripts you want to scan for bad globals. After the scripts you want to scan, run BADGLOBALS.check() and watch firebug. This script will only work in Firefox or Chrome, NOT in Internet Explorer. Copied from http://www.adequatelygood.com/Finding-Improper-JavaScript-Globals.html

BADGLOBALS.js

/*jslint white: true, onevar: true, devel: true, undef: true, nomen: true, eqeqeq: true, plusplus: true, bitwise: true, regexp: true, strict: false, newcap: true, immed: true */
/*globals window: false */

/* Copied from http://www.adequatelygood.com/Finding-Improper-JavaScript-Globals.html */

// Include this script BEFORE any scripts you want to scan for bad globals.
// After the scripts you want to scan, run BADGLOBALS.check() and watch firebug.
// This script will only work in Firefox or Chrome, NOT in Internet Explorer.
var BADGLOBALS = (function (window) {
    var report,     
        skip = [],
        that = {
            check: function (exclude) {
                var prop,
                    val,
                    bad = [],
                    good = [],
                    skipped = [];
                
                exclude = exclude || [];
                
                for (prop in window) {
                    if (window.hasOwnProperty(prop)) {
                        if (skip.indexOf(prop) >= 0 || exclude.indexOf(prop) >= 0) {
                            skipped.push(prop);
                        } else {
                            val = window[prop];
                            if (delete window[prop]) {
                                console.warn("Found non-var global %o with value %o", prop, val);
                                bad.push(prop);
                                try {
                                    window[prop] = val;
                                } catch (e) {
                                    console.error("Oops, there was an error putting %o back :(", prop);
                                }
                            } else {
                                good.push(prop);
                            }
                        }
                    }
                }
                report = {
                    bad: bad,
                    good: good,
                    skipped: skipped
                };
            },
            exclude: function () {
                var i = 0,
                    l = arguments.length;
                
                for (; i < l; i += 1) {
                    skip.push(arguments[i]);
                }
            },
            report: function () {
                if (!report) {
                    that.check();
                }
                return report;
            }
        },
        prop;
    
    for (prop in window) {
        if (window.hasOwnProperty(prop)) {
            skip.push(prop);
        }
    }
    
    return that;
}(window));

Great work. I've been meaning to write something like this myself. It's a shame there no easy way of doing it in the browser console but hey.