I am not a web programmer, so please excuse my ignorance. When it comes to server side programming, we have plethora of technologies available, such as PHP, ASP.net, JSP and so on.
However, when it comes to client side scripting, I have only heard of JavaScript and AJAX. Maybe you can also include Java Applets, as they run on the client. A relatively new one is also the Google's native client. But are there any more client side technologies which exist and are popular?
AJAX is just a buzzword, it's not a language. Google's Native Client is similar to NSAPI, you can use it to create plugins (it doesn't really count). Google is also pushing a new client-side language called Dart that will probably go nowhere, and old IE versions support VBScript.
So, you have JavaScript, VBScript (sort of) and Dart (sort of).
So far JavaScript is the only ubiquitous client-side technology, as Flash fades away. Google works on Dart language which they expect to make a replacement for JavaScript, and there exist several other less popular things (CoffeeScript, Opa etc). All mentioned ones (starting with Dart) are either run out of browser using their native interpreters or are compiled into JavaScript for client-side use. There also exists GWT, a toolkit that lets you write in Java and compile the code again to JavaScript.
Adobe Flash is very popular ;) and also Activex...
Some of the client side scripting languages are Python, Perl and there's Ruby too etc...But mostly, all server side ones are capable of client side programming.
来源：https://stackoverflow.com/questions/9649123/client-side-languages