Alternative to HTML for Cloud Programs

Note: This is not intended as a REPLACEMENT for the web as it is, but as an ALTERNATIVE. By its nature, it would allow for cloud based applications that look and feel much more like a native application, and should be billed as such.

Consider a  "web browser" that thinks in a manner much more like a local application. It would use a toolkit which provides native themes (I'm considering using GTK+ for the reference implementation) and a set of widgets/components to work with, as well as an interpreted language which would cover the content, layout, formatting, and scripting of the web page.

Because all code is interpreted by the web browser, the implementation can prevent malicious code by running it in a sandbox. An example (and I believe safe) implementation would give each "web application" access to a sandboxed virtual filesystem in which it can store everything from settings to passwords to databases. Reading and writing files outside of the sandbox would be possible, but only by direct user action; it would not be able to read, run, or edit files without asking for permission (and probably requiring a file browser dialog for each file). This would allow the uploading of local files while preventing the application from stealing data.

Attached I have proposed an example of what the code would look like when it is written. It would be compiled to an obfuscated/minimal version by the server before being sent to the browser.
http://pastebin.com/44JHrEtq

Comments and opinions would be appreciated.

This is bad. Don't invent a new (and quite terrible) language, you're just creating more problems for yourself. Just use or write a templating system for an existing language. That way, nobody will be put off learning this new language when they can use what they already know instead.