weinre.web/client/weinre/check-for-webkit.js

/*
 * weinre is available under *either* the terms of the modified BSD license *or* the
 * MIT License (2008). See http://opensource.org/licenses/alphabetical for full text.
 *
 * Copyright (c) 2010, 2011 IBM Corporation
 */

if (!navigator.userAgent.match(/webkit/i)) {
    alert("This web page is only designed to work in WebKit-based browsers.  Sorry.  Best of luck.")
}