Question

I have some troubles with this regular expression in javascript. That same regex works in PHP, but in JavaScript this error occurs: “Invalid regular expression: unrecognized character after (?”. My regular expression is:

text = text.replace(/(?<!\=\")http([A-Za-z0-9:\/\.\+\?\%\@\!\#\&_-]+)/g,
    '<a href="http$1" target="_blank" rel="nofollow">http$1</a> ');

The problem is in first part (?< !\=\") but I don’t know how to solve it because it is a normal regular expression for PHP or C.

Is there any analog of this construction? I need to disallow symbol " (double quotes) right before “http” for preventing url replacements in html elements like <img>.

I’m edit the question because the symbols < plus ! make an error in displaying text after it. (that, may also invoke error).

Answer 1

In your example above (including adding the ):

var text = 'something bla bla bla like this domain.com/blabla/bla.php or more. <img src="img.com" />'

This would work for you:

var newText = text.replace(/([^ ]*\.com\/[^ ]*)/g,'<a href="http://$1"; target="_blank" rel="nofollow">$1</a>');

And outputs:

something bla bla bla like this <a href="http://domain.com/blabla/bla.php"; target="_blank" rel="nofollow">domain.com/blabla/bla.php</a> or more. <a img src="img.com" />

Basically it recognizes the url by anything not a space in front of a .com/ plus anything afterwards not a space. It won’t grab the <img src="img.com" /> as that’s a .com".

If you only have .com domains this will work, if you have .net, .org, etc, etc. then you’ll have to add those as things to check.