Question

Below code works well, its able to replace any tag it find with a link, but tags with existing links are also replaced, like @google which should be ignored.

<div class="post">
    <p class="test">First text some @microsoft</p>
    <p class="test">Second text with <a href="http://www.google.com">@google</a>, @yahoo</p> 
    <p class="test">Third text with @apple, @stackoverflow</p>
</div>  


$('.post p.test').each(function (i, el) {
    $(el).html($(el).html().replace(/\B\@([\w\-]+)/gim, function (match, username) {
        return '<a href="http://www.twitter.com/' + username + '">' + match + '</a>';
    }));
}); 

I have had no luck with regex, I want jquery to ignore tags with existing link: http://jsfiddle.net/ereXZ/1/

Answer 1

You can try a negative lookahead (?!</a>) after your link regex, see updated jsfiddle

Note that the [\w\-]+ has been changed to [\w\-]+\b(?!</a>). The \b makes sure the regex matches up to the end of the tag, and the (?!</a>) makes sure tags followed by a closing link tag are not matched (and the / needs to be delimited).