If you are looking for an easy reliable solution to use in your project, here are 10 useful libraries that can work in all modern browsers and will add options to annotate the web.
Annotation plugin for Chart.js. This plugin draws lines, boxes, points and ellipses on the chart area. Annotations work with line, bar, scatter and bubble charts that use linear, logarithmic, time, or category scales. Annotations will not work on any chart that does not have exactly two axes, including pie, radar, and polar area charts.
An infinitely customizable image annotation library built on React.
react-pdf-highlighter is a React library that provides annotation experience for PDF documents on web. It is built on top of PDF.js by Mozilla. Text and rectangular highlights are supported. Highlight data format is independent of the viewport, making it suitable for saving on the server.
A plugin for video.js to add support for timeline moment/range comments and annotations.
Powerful React component for image annotations with bounding boxes, tagging, classification, multiple images and polygon segmentation.
Use d3-annotation with built-in annotation types, or extend it to make custom annotations. It is made for d3-v4 in SVG.
Small and simple JS tool for making powerful underline, highlight and strike text annotations.
An open-source, web-based ‘multi-up’ viewer that supports zoom-pan-rotate functionality, ability to display/compare simple images, and images with annotations.