Vanilla JavaScript Plugin

Croppr.js  

An image cropper that's lightweight, awesome, and has absolutely zero dependencies.

Plugin Website  Demo

Related plugins

Image Crop Component  

Crop images with configurable aspect ratio, minimum and maximum dimensions, etc. Great, but requires a license.

DragSelect  

Select any DOM element by clicking and/or dragging with your mouse just like you would in a desktop app.

mark.js  

A highlighter plugin that can be used to dynamically mark search terms or custom regular expressions in any text.