JavaScript RegExp replace HTML comments

Question

I'm searching a way to replace all html comments from a string like browser does. (multilined and unclosed)

For example, I actually use /(<\!--[\s\S]*?-->)/gim but if the html comment is unclosed, it does not replace it.

Normally, if the comment tag is not closed, comment tag gets everything after open tag...

Is there a way to adapt the regexp (or any other regexp) to do the stuff ? (in JavaScript)

[This is a bad idea.](http://stackoverflow.com/a/1732454/102937) — Robert Harvey, Jul 15 '14 at 22:50
*"but if the html comment is unclosed, it do not replace it"* which seems reasonable, since you don't know where the comment ends. What's the behavior your want to achieve? Either way, you cannot reliably remove comments this way. What if you have an HTML element with attribute value `"--> foo"` for example? — Felix Kling, Jul 15 '14 at 22:52

Andie2302 · Accepted Answer · 2014-07-16T12:25:20.347

1

This will mark all comments also the one without end tag: 

<!--[\s\S]*?(?:-->|$)

This will mark all comments also the one without end tag: 

<!--[\s\S]*?(?://-->|$)

This will mark everything from the first <!-- to the very end of the file

<!--[\s\S]*?(?:$)     and regex set to `^$ don't match at line breaks`

This will mark everything from the first <!-- to the end of the line

<!--.*

edited Jul 16 '14 at 12:25

answered Jul 16 '14 at 00:05

Andie2302

This regex get the comment entirly, also if the comment is unclosed but it do not get everything after comment opening. Exemple: if I have this HTML code "
hello world!
", the regexp stop before the "p" tag. In HTML if an comment is open is open but not closed, everything is commented, I want to approach this way. But its so close. – Jordan Jul 16 '14 at 09:45
@Jordan The regex stops before the
tag because the --> marks the end of the comment.
– Andie2302 Jul 16 '14 at 11:57
Sorry, i meant " – Jordan Jul 16 '14 at 13:09
I finally found a regexp that work: "(<\!--[\s\S]*?(?:-->|$))/gi". I'm gonna 'answer my own question'. Thanks for your help. – Jordan Jul 16 '14 at 22:52

score 0 · Answer 2 · edited May 23 '17 at 12:32

0

I must agree that using regex like this is not good practice and you shouldn't do it... here's why.

Buuuut, as a matter of understanding regex better, you can make something optional like this:

/(<\!--[\s\S]*?(?:-->)?)/gim

I wrapped --> in parenthesis to group it together
I put a ? after that group to make it optional
(not necessary) I put ?: inside of the group to keep the regex engine from saving a back reference... it's a performance nuance.

edited May 23 '17 at 12:32

Community

answered Jul 15 '14 at 23:53

Ryan Wheale

score 0 · Answer 3 · answered Jul 16 '14 at 23:08

0

Thanks to @Andie2302 for the help.

This regexp /|$)/gi work find.

Do not use the flag m!

answered Jul 16 '14 at 23:08

Jordan

3 Answers3