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: 
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> I know that CSS used to style HTML docs, but is that the only way ? 
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It is the only sensible way

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> Can I use JavaScript to style HTML, somehow ?
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You can generate CSS with JavaScript. (Not advisable for general styling).

You can use [JSSS](http://en.wikipedia.org/wiki/JavaScript_Style_Sheets) if you're only targeting Netscape 4.x.
I suppose the correct answer to your question is no, because html includes some basic style elements itself. But CSS is the best way to style your documents and you absolutely should learn and use it. Once you're comfortable using CSS, try using a framework such as [Twitter bootstrap](http://twitter.github.com/bootstrap/) to make your life easier.