This application is a JavaScript built file comparison utility. All logic is performed in the browser with no data being sent back to a server for processing. The core algorithm used to compare files is the longest common sequence algorithm. Lines only appearing in the left file are marked in red, while lines only found in the right file are in yellow. Lines common to both files have no color. Because of security restrictions in current browsers, file contents need to be pasted into the left and right text areas for file comparison.