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81

Remove HTML comments with Regex, in Javascript

rated 0 times [ 85] [ 4] / answers: 1 / hits: 44228 / 13 Years ago, wed, april 13, 2011, 12:00:00

I've got some ugly HTML generated from Word, from which I want to strip all HTML comments.

The HTML looks like this:

<!--[if gte mso 9]><xml> <o:OfficeDocumentSettings> <o:RelyOnVML/> <o:AllowPNG/> </o:OfficeDocumentSettings> </xml><![endif]--><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:HyphenationZone>21</w:HyphenationZone> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:DoNotPromoteQF/> <w:LidThemeOther>NO-BOK</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w:EnableOpenTypeKerning/> <w:DontFlipMirrorIndents/> <w:OverrideTableStyleHps/> </w:Compatibility> <m:mathPr> <m:mathFont m:val=Cambria Math/> <m:brkBin m:val=before/> <m:brkBinSub m:val=&#45;-/> <m:smallFrac m:val=off/> <m:dispDef/> <m:lMargin m:val=0/> <m:rMargin m:val=0/> <m:defJc m:val=centerGroup/> <m:wrapIndent m:val=1440/> <m:intLim m:val=subSup/> <m:naryLim m:val=undOvr/> </m:mathPr></w:WordDocument> </xml><![endif]-->

..and the regex I am using is this one

html = html.replace(/<!--(.*?)-->/gm, )

But there seems to be no match, the string is unchanged.

What I am missing?

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angelicajayleneh

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3 Years ago

answered 13 Years ago monetm · Accepted Answer

The regex //g should work.

You're going to kill escaping text spans in CDATA blocks.

E.g.

<script><!-- notACommentHere() --></script>

and literal text in formatted code blocks

<xmp>I'm demoing HTML <!-- comments --></xmp>



<textarea><!-- Not a comment either --></textarea>

EDIT:

This also won't prevent new comments from being introduced as in

<!-<!-- A comment -->- not comment text -->

which after one round of that regexp would become

<!-- not comment text -->

If this is a problem, you can escape < that are not part of a comment or tag (complicated to get right) or you can loop and replace as above until the string settles down.

Here's a regex that will match comments including psuedo-comments and unclosed comments per the HTML-5 spec. The CDATA section are only strictly allowed in foreign XML. This suffers the same caveats as above.

var COMMENT_PSEUDO_COMMENT_OR_LT_BANG = new RegExp(

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

    + '<!---+>?'  // A comment with no body

    + '|<!(?![dD][oO][cC][tT][yY][pP][eE]|\[CDATA\[)[^>]*>?'

    + '|<[?][^>]*>?',  // A pseudo-comment

    'g');