greasemonkey_alter_assets_paths.js

// ==UserScript==
// @name        capybara serving assets
// @namespace   http://studio.pixarea.com
// @description adds base tag to serve assets in pages generated by capybara's "save_and_open_page"
// @include     file:///*/tmp/capybara/capybara-*.html
// @version     1
// @grant none
// ==/UserScript==


// Note: you need to enable GreaseMonkey for local files for this to work:
// type "about:config" in the Firefox address bar, and set extensions.greasemonkey.fileIsGreaseable = true

for( i = 0; (l = document.getElementsByTagName("link")[i]); i++ ) {
    if( l.getAttribute("rel").indexOf("style") >= 0 ) l.href = l.href.replace("file:///cucumber_test_assets/","http://localhost:3000/assets/");
}