I had another problem, I did not want to encode data in gzip but to decode gzipped data.
I am running javascript code outside of the browser so I need to decode it using pure javascript.
It took me some time but i found that in the JSXGraph library there is a way to read gzipped data.
Here is where I found the library: http://jsxgraph.uni-bayreuth.de/wp/2009/09/29/jsxcompressor-zlib-compressed-javascript-code/
There is even a standalone utility that can do that, JSXCompressor, and the code is LGPL licencied.
Just include the jsxcompressor.js file in your project and then you will be able to read a base 64 encoded gzipped data:
<!doctype html>
</head>
<title>Test gzip decompression page</title>
<script src="jsxcompressor.js"></script>
</head>
<body>
<script>
document.write(JXG.decompress('<?php
echo base64_encode(gzencode("Try not. Do, or do not. There is no try."));
?>'));
</script>
</html>
I understand it is not what you wanted but I still reply here because I suspect it will help some people.
