Here is EditArea, a free javascript editor for source code. It allow to write well formated source code with line numerotation, tab support, search & replace (with regexp) and live syntax highlighting (customizable). This project is no more supported.
Contributions:31 commits, 1 PR, 1 push in 9 years 7 months
javascriptregexsyntax-highlighting
Contributions:5 pushes in 9 years 8 months