This problem seems to be a upstream problem. If there are ,,--'' inside of a HTML comment of a web page the rendering engine gets completely wrong. There are not always the same visible effects but mostly rendering failures. See the example HTML page and compare the output of firefox with other graphical browsers or with the expected result. --- SNIP --- <html> <head> <title>Testpage</title> </head> <body> Test4 <h1>Test1<h1> <!-- ---++%SPACEOUT{"Fail"}% --> <p> Test3 <h1>Test2</h1> </body> </html> --- SNAP ---
I made a mistake in the code. Use this to reproduce the bug: --- SNIP --- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http:// www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-us" lang="en-us"> <head> <title>Testpage</title> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /> </head> <body> <h1>Test1</h1> <!-- ---++%SPACEOUT{"Fail"}% --> </body> </html> --- SNAP ---
See https://bugzilla.mozilla.org/show_bug.cgi?id=214476 for a detailed explanation. Firefox is actually correct here. The comment delimiter is actually -- per SGML. Your markup has three double-dash sequences: <!-- ---++%SPACEOUT{"Fail"}% --> -- -- -- ^ ^^^^^^^^^^^^^^^^^^^^^^ The first -- opens the comment, and there is a space commented out. But then you close it out with the next two dashes, so the rest is displayed. Finally, you close the comment again with the last two dashes and anything you would add after that would be commented. Bottom line is, Firefox is following the spec. If the HTML is intended to be commented, then it is wrong. :-)