This is a fail. (1) It tries to open a new window to display the result, so you'll probably get a "popup blocked" warning every time you invoke it. (2) It colors some of the text a hideous purple. An anti-feature, imo. (3) The 1st page I tried (example.com/) was reformatted to be less reader-friendly than the original. (4) It omitted 2/3 of the content in the 2nd page I tried (www.tutorialspoint.com/tcl-tk/index.htm)

Not dangerous, but not useful either.