Javascript

i dont really understand how javascript will hlp me in any way when i am making a website?...what is javascript for and can't i substitue it for soemthing else?do i really need to learn it?

i dont really understand how javascript will hlp me in any way when i am making a website?...what is javascript for and can't i substitue it for soemthing else?

JavaScript allows you to add client-side scripting to your site, to do all sorts of things with your website. It can be used to build interfaces, perform calculations and dynamic programming, create effects and pretty much anything a client-side programming language can do. Substituting it for something else is sometimes possible, but there is no one replacement to replace the functionality of JavaScript. For example, some functionality can be replaced with PHP, some with Apache modules, some with Perl/CGI, and some functionality is difficult or impossible to replace.

do i really need to learn it?

You certainly don't have to. You can make perfectly good websites without using any Javascript at all. Javascript can, however, help to improve some websites if used correctly - but is by no means essential.