What happens to my web application if JavaScript is disabled?

I'm learning jQuery and am about to write some pages using intensively that library. I just learned that some user disable JavaScript on their browser (I didn't even know that was possible and/or necessary开发者_开发知识库).

Now, here's my question: What happens to my web application if a user disable JavaScript? For instance, I'd like to display some screens using AJAX and commands such as 'InsertBefore' to bring in live a DIV that will display the result.

So, if JavaScript is disabled, I wonder what going to happen to all this work that relies on JavaScript?

I'm kind of lost.

Thanks for helping

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You may want to start by reading on Progressive Enhancement and Unobtrusive JavaScript.

I would also suggest to investigate how popular rich web applications like GMail, Google Maps and others, handle these situations.

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I just learned that some user disable javascript on their browser

I do. The "NoScript" plugin for FireFox does the trick.

So, if Javascript is disabled, I wonder what going to happen to all this work that relies on Javascript?

It won't be functional.

A good practice suggests designing a site not to rely on JavaScript for major functionality. At least, accessing its content (in read-mode) should be possible. JavaScipt should only add interface enhancements like Ajax techniques etc. But the fallback version should always work.

I feel really sad when I see a site which is completely broken without JavaScript. Why can't people use CSS to put elements in proper places? Why do they try to align elements with JavaScript even if there is no dynamics involved?

The same goes for Flash sites. Once in a while a land upon a "web-design-agency" site which makes picky comments about me not allowing JavaScript. When I do I only see a basic primitive site with a few menus and that's it. What was the point of using Flash when the work is so primitive it can be done with raw HTML and CSS in an hour? For me it's a sign of unprofessional work.

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All what's done in JavaScript won't work. Some users disable it for security reasons, NoScript is an excellent example. You can try it yourself by removing the scripts from your page or installing the NoScript-plugin for Firefox.

As a rule of thumb:

1. Make the website working with only semantic HTML
2. add the CSS
3. add the JS

But the website should be (almost) fully functional in stage 1.

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If you disable Javascript in Safari things like Lexulous in Facebook won't work properly, the mouse letter carry function doesn't work.