Put your comments on a side.

Looks very clean and intuitive. Link here.

Charting library using d3.js framework

Link here.

Amazing js library to give superpowers to your css and js! A lot of features with pretty nice documentation.

Link here.

Nice ways to curve your text

Link here.

Authentication techniques in AngularJS

Link here.

Better solution for simple loading gif

Use cross platform spin.js. Link here.

Use java libraries with nodejs

Link here.

Build your own jquery wih modules you require

Link here.

Drag and drop interface builder

If you're looking to startup with your frontend code and quickly want to setup the base with bootstrap, Layoutit is a great way to start with. Link here.

Check if your page is visible currently via javascript

Link here.

Learn how to use flexbox to position elements

Link here.

Extract and manipulate rar files using javascript !

Link here.

Really cool concept of automatically switching to lighter or darker version of an element depending on the brightness of images behind it.

Link here.

A quick 3 minutes introduction to Bower( Javascript Package Manager)

Link here.

A nice and minimalistic progress bar

Link here.

Coolest ever page transitions !

Link here.

Preload assets(eg. images) on your page

Link here.

Know which css is going unused

Link here.

Tired of figuring out how to vertically(or horizontally) center your elements? Here's a javascript plugin!

Link here.

Get placeholder images according to your need when designing a new web app

I could find not one but three of them. Besides choosing sizes, we can also choose type of images we want from categories provided, all for free.

Lorem Pixel
Fakeimg
Placeimg