I want something which can run purely on the client. I don't need any server interactions, database at most. Ive been using php but want a change, any suggestions?
javascript and it's not even close, but you'll never get a DB interaction without the server side - JS can at most offer you AJAX to do the comms transport.
edit: fwiw I'm guessing you are probably used to quite an old methodology of development, if you were a windows developer I'd suggest you look at asp.net/c#, I'm not sure what a similar entry-level LAMP alternative would be, somebody else will know. JSP? Cocoon?
what about python and perl? are there any variations of these that can be used client side?
What do you mean with "on the client"? Should that imply "in a Browser"?
Inside the browser you don't really have much choice (if you don't want to restrict your audience too much). JavaScript and possibly Ruby, but that's about it.
if your not talking about the browser, then you can choose whatever you want. Pretty much every language that you can use on the Server works on the Client as well. Python, Ruby, Lua, JavaScript, Perl, ...
The question for "best" can't really be answered, because it depends entirely on your requirements.
Perl and Python are perfectly capable of running purely on the client. In fact, PHP is the language that used to force a distinction between server and client:
PHP is a scripting language originally designed for producing dynamic web pages. It has evolved to include a command line interface capability and can be used in standalone graphical applications.
Python is a general-purpose, high-level programming language. Perl is a high-level, general-purpose, interpreted, dynamic programming language. Both languages are available on many operating systems and have extensive libraries to facilitate many operations on the local system. My personal preference is Python.
You should consider Python and LUA. Both can be compile as a library which you can embed easily in some bigger application.
LUA is smaller, Python has the easier syntax.