Add more JavaScript Tips!

[vyasriday]

Add more javascript tips and raise a PR.

[femakin]

Please how do I contribute to this?

[vyasriday]

@femakin check for existing tips. If you know something that can help people in JavaScript you can add yours too

[yashi12]

I would like to work on it. Can I add important topics that should be read in JavaScript?

[vyasriday]

@yashi12 Yeah please feel free to add.

[yashi12]

@yashi12 Yeah please feel free to add.

I have added the PR(#8). Please have a look at it, and merge it.