What I want to do is be able to see how it will look any website with my javascript attached . I want to create something like selectorgadget working on any website.
The first idea is to use a proxy (eg privoxy) and define a regular expression changing in html: </head> to <script src="http://myserver.com/my_javascript.js"></script></head>. It works, but in such case, I need to set proxy in my browser. And it is not cool because It visible only for me.
Another idea is to write a website that will download page under the hood and show it. How it will work:
Go to page eg.: http://myserver.com/
My index.php will download eg.: www.google.com using http client or curl, replace page source (add my
<script>before</head>) and return page to user. It works, but when page contains relative images I'm not able to see it. Rewriting image src, and other script src is not so simple.
Because I want to add only javascript, I thought that you can use iframes. But there is a restriction to the same domain.
Any ideas on how to do it? Maybe some tool? Something with cross-domain iframe?