User-Agent: Build Identifier: Mozilla/5.0 (Windows; U; Win 9x 4.90; en-US; rv:1.6) Gecko/20040113 Including two consecutive hyphens (dash, minus sign) within a comment causes the text of the comment itself to display and otherwise displayable text to disappear. The behavior changes slightly if there is a second comment which contains any text which appears to be an HTML tag (even if the tag is bogus). Reproducible: Always Steps to Reproduce: 1. Here is a code fragment which shows the problem: Here is the first way to see the problem<br> <!-- This is a comment showing the problem of the -- double hyphen --> <br>This text is hidden by the double hyphen bug<br> <!-- <p>This text magically appears even though it's a comment --> Here is a different way to see the problem<br> <!-- A second comment showing the problem -- differently --> <br>This text appears regardless because there's no tag in the next comment<br> <!-- This text contains no HTML tag, hence doesn't display --> Even a bogus tag (for example, <bogus>) makes a difference Actual Results: Some text one expects to see is hidden. Some text one expected to be invisible because it occurs within a comment is displayed. The simple workaround is to not have hyphens in sequence, either by removing the second hyphen or by separating them with a space. Expected Results: Hide all text within a comment. Display text outside comments.
> The simple workaround is to not have hyphens in sequence Which is what the HTML spec clearly says authors should do. The reason is that in HTML "--" is that character sequence that both starts and ends comments. In quirks mode, we treat "<!--" and "-->" as the start/end sequences, but in standards mode, which your test pages must be triggering, we actually do correct comment parsing.
*** Bug 305122 has been marked as a duplicate of this bug. ***
*** Bug 361731 has been marked as a duplicate of this bug. ***