Question: I am a beginner web-designer. I know the basics of HTML, CSS and Javascript. I know that CSS used to style HTML docs, but is that the only way ? Can I use JavaScript to style HTML, somehow ? Or Is there any other way rather than CSS ?

Answer: 
It's not the only way but the recommended way.
You can include styling in your html tags but it becomes messy.
That's why CSS was invented so use it !
As mentioned previously, CSS is not the only way to stylize HTML but definitely the standard. If you're looking for a more programmatic way utilizing JavaScript you can look into [less](http://lesscss.org/) which (taken directly from the webpage) ...extends CSS with dynamic behavior such as variables, mixins, operations and functions and functions map one-to-one with JavaScript code, allowing you to manipulate values however you want.