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: 
JavaScript is a scripting language, not a styling language. While you can use JavaScript to apply CSS, it's still CSS, not JavaScript, that's defining the styles.

There exist HTML presentational attributes from [a long time ago](http://www.w3.org/TR/REC-html32), but those have been superseded by CSS. You can still use them, not that you would want to, considering they'll most likely get translated to CSS anyway.

There also exist CSS preprocessors with custom languages, such as [Sass/SCSS](http://sass-lang.com), [LESS](http://lesscss.org) and [Stylus](http://learnboost.github.com/stylus), but they all compile to CSS as well, because that's what's actually implemented by browsers. So even if you use these preprocessors, at the end of the day you're still "writing" CSS.
You're also able to style HTML with HTML-attributes itself, but this way is pretty impractical and old-fashioned. Most of these techniques are deprecated and the functionality is VERY limited.