JustLines is an extension for Chrome that can be used as an alternative for the Pen tool in Google Chrome. You can draw simple lines in your browser by using the wheel of your mouse. The color of the lines is also customizable so you can highlight a specific section of a page without losing your current position.

You can change the color and size of the lines and also the color of the background. You can also use the same extension to change the color of any other element on a web page, such as a button or a logo.

The extension is useful to make presentations, it can help you highlight important parts of a slide and make schemas. You can use this extension for web presentations and also for ebooks or PDF files.