Welcome to the web :)

I can recommend Yii (PHP MVC framework) which can help you get going quickly. It comes with a code generator and also takes care of things like JavaScript form validation and other front-end related things.

Personally, I like to only use JavaScript frameworks/libraries if they are really required. If you need to do a lot of stuff dynamically on the front-end, you can also look into libraries like Backbone, which give you a nice tool belt but keep things more flexible.

Have fun! :)