What is JavaScript good for and what are its general limitations?

-Just want to know the main points of what its good for and what types of functions would be better written in some other language like php.Some people think JavaScript is only good for popups and form validation. Actually, Gmail, Google Maps, Google Analytics... all those powerful tools are all implemented in JavaScript (the client side). With HTML5 you can even have TCP sockets that keep a connection open with the server ( example http://www.youtube.com/watch?v=oJxWhmt5m鈥?/a> ). There are even complete 3D games that you can play in the browser written 100% in JavaScript (with WebGL, which is a way to have OpenGL in the browser through JavaScript). Basically, if you want to be a powerful web developer and write rich, dynamic, and desktop-like apps on the browser, you have to master JavaScript. No, it is not a true Object Oriented language (like C/C++ or Java or C#), but it is still very powerful. But very importantly, it is the language that runs on the most used platform in the world - the browser.



For more information, check out the Google TechTalk presentation given by Doug Crockford, one of the current developers of JavaScript. He talks more about what JavaScript is good for, and what some of its limitations are. He also talks about future plans for the language.
JavaScript can make dynamic changes to the page and send direct user output. Because it is a browser side language. Php for one is server side, so forget a jumping around page, unless you use video, which I bigot disrecommend.

So JavaScript can dynamically alter a page, send direct (e.g. Popup) user output, redirect/get URL/change URL/get other window information dynamically.

But all the code is visible unless you use asp. Asp won't be trigerred as well though.

Btw asp is basically JavaScript or vbscript potted to server side.