I developed a jQuery plugin called jTestSize (jST) that provides real-time measurements of the document, viewport, and device dimensions on an HTML page as a convenient widget.

Designed for easy integration, jTestSize is lightweight and helps developers optimize user interfaces by displaying critical measurements in real time, ensuring better responsiveness across various devices.

With jST, users can quickly assess how their content appears on different screen sizes, making it an essential tool for efficient testing and design adjustments.