Trimming comments in HTML documents using Apache Ant

Posted on September 20 by Julien Lecomte

This short article, explaining how to trim unnecessary code (comments, empty lines) from HTML documents, is a follow-up to an article published a couple of weeks ago on this blog: Building Web Applications With Apache Ant. Basically, the idea is to use Ant’s optional replaceregexp task as shown below:

<target name="-trim.html.comments">
    <fileset id="html.fileset"
        dir="${build.dir}"
        includes="**/*.jsp, **/*.php, **/*.html"/>
    <!-- HTML Comments -->
    <replaceregexp replace="" flags="g"
        match="\<![ \r\n\t]*(--([^\-]|[\r\n]|-[^\-])*--[ \r\n\t]*)\>">
        <fileset refid="html.fileset"/>
    </replaceregexp>
    <!-- Empty lines -->
    <replaceregexp match="^\s+[\r\n]" replace="" flags="mg">
        <fileset refid="html.fileset"/>
    </replaceregexp>
</target>

Update: Use this code very carefully as it is dangerous territory (Thanks to my co-worker Ryan Grove for pointing out some of the shortcomings)

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6 Responses to Trimming comments in HTML documents using Apache Ant

  1. Mike Henke says:
    September 20 at 6:32 pm

    Awesome. Keep the ant scripts coming they are great.

  2. Pingback: Web Application Construction Tools » Chris Norton

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  4. Steve says:
    September 28 at 11:15 am

    How do you prevent the regex from removing Javascript enclosed in HTML comments in order to hide it from browsers, which have Javascript disabled?
    I fiddled around a lot but never managed to get ant ignore comments which end with //->. It always results in an infinite loop. :-(

  5. Julien Lecomte says:
    September 28 at 11:53 am

    @Steve

    Do not wrap inline JavaScript code inside HTML comments. Nobody uses Netscape 1 anymore…

  6. Jaime Bueza says:
    February 18 at 5:58 pm

    Here’s one for removing console.log within a combined yui compressed file.


    <replaceregexp file="my_combined_file.js" match="(console\.log\(.*\))" flags="g" replace="\/\/\1"></replaceregexp>