Which browser-based client-side technology?

Back in the day there were only Active X and JavaScript.

Users would turn them off, disabling my apps, or would edit the JS code (usually breaking it). So I switched to strictly server-side, where I have complete control.

Now I am thinking that I might be misisng out on half of the possibilities for browser-based apps.

We are talking business apps here, so maybe I can enforce JS. I guess that Active X gave way to .NET long ago, but what's a good matching client-side tech?

I am a Linux fan and would be happy with a cross-platform solution, but, realistically, 90+% of 开发者_JAVA百科bussinesses are using Windows and insting on MS IE, no even firefox (at least here in Asia, ymmv)

What's the current state of play, and is there anything that addresses my concerns above?

@Oren A makes a good point about about combining client & server side. For server side I have been mainly using PHP but recently have done some .NET stuff (in both C# and VB), and some SOAP. What's a good combination of client/servertthat works well together? Or do you think them totally independant?

You have JQuery (which is a JS library) and dojo (which is a JS toolkit), and if you need more advanced capabilites - there's Flash (there's also Silverlight, but I don't think you'll like it (-:. Should add that both Flash and Silverlight are downloadable plug-ins and that Flash is more popular, but you can read all about that by googling). Obviously there are many more, but those are the most popular AFAIK.
Flash files are sended to the user "semi-compiled" so he can't mess with them (although I really don't see how that's a problem in the first place).
Anyhow the vast majority of web application use both - client side and server side programming languages.
.NET is mostly sever side (Although web forms are somewhat of a client side as well..).
And one last thing - If a user changes your JavaScript and the script doesn't work for him - why is that a problem for you? unless you're talking about XSS, which you really do need to be aware of..

A bit late, but there is a technology that is useful when you go to the client side.
Javascript template engines, they usually take a JSON as data input, and render the HTML client side.
They help you separate the HTML view and the Javascript logic.

I'm contributing to PURE which has a quite unobtrusive approach on strictly separating the HTML markup and the JS logic.
There are plenty of other templating solutions if you look on the web. They are mostly based on the Django template pattern (with tags inside the HTML)