TextCompare

Text Compare! is an online diff tool that allows you to easily make a text comparison and find the differences between two texts. Just paste the two texts and hit the compare button. The two texts are shown side by side, with differences highlighted. It highlights not the entire line which contains a difference, but only the difference itself. For larger texts, it also has links that allow you to jump from one difference to the next. Text Compare! does not save or share the text you compare. If you have sensitive information to compare, however, it is still recommended to use an offline tool.

Active File Compare is an advanced utility for the comparison and synchronization of any text files in visual mode, it reports the results of the comparison in two side-by-side windows on the screen, the differing lines being marked with special color icons. This utility is an excellent tool for comparing source code versions since it allows you to correct the source code and also supports syntax highlighting for the programming languages C++, C#, Java, Visual Basic, Delphi, Object Pascal, SQL, Perl, Assembler, Fortran, Foxpro etc. and for HTML, PHP, XML, INI and BAT files. You can also use it to manage the source code when several independent authors make changes. The algorithm of comparing is designed in such a way that it's always very accurate in finding differences both in small text files and in files with a large number of changes. Active File Compare has its own file manager consisting of two side-by-side windows.