Hello guys could you please explain an newbie how these technologies are different from each other?

PHP is a server side programming language, which is ran into the web server when a page is generated, before being sent to the browser.

Javascript is a client side scripting language, that run into the browser, and is allowed to interact with the element that are present into the page.

PHP run only during the page load. Once the page is loaded, no more PHP can be run.
Javascript starts only when the page is received.

Unfortunately it's a little more complicated than that...

Javascript can be run on servers that support it. ASP pages can use javascript instead of vbscript.
The Apache Sling server supports ESP (Ecma Script Pages) which are basically JSP's that use Javascript instead of Java. Any J2EE container can use server side javascript by including the Rhino library. Actually, by using that library, any java program can include Javascript support (client, server, whatever).
On linux you can build desktop applications using DCOP and Javascript. On Windows, you can do something similar in HTAs. In both of these cases, javascript gets access to the filesystem, network, and various system internals.

PHP doesn't only have to be used on the server. Many people are now building PHP desktop applications. I think it's crazy but, that's another matter.
A quick search will give you lots of info on that.

Basically these are just different dynamic loosely-typed scripting languages. Tripy pointed out the primary ways you will see them in the web world. If you are learning, get started with Javascript first. It's a natural next step from HTML. The best thing with learning it, you don't need any tools or setup. Your web browser is your runtime engine, and text editor, your development tool.

Writing server code can be your next step after javascript.