detect url's in text with Javscript/Prototype.js

Question

Does anyone have suggestions for detecting url's in a set of elements and converting them to links?

$$('#pad dl dd').each(function(s){
   //detect urls and convert to a elements.
});

Answer 1

First you need a good regex that matches urls. This is hard to do. See here, here and here:

...almost anything is a valid URL. There are some punctuation rules for splitting it up. Absent any punctuation, you still have a valid URL.

Check the RFC carefully and see if you can construct an "invalid" URL. The rules are very flexible.

For example ::::: is a valid URL. The path is ":::::". A pretty stupid filename, but a valid filename.

Also, ///// is a valid URL. The netloc ("hostname") is "". The path is "///". Again, stupid. Also valid. This URL normalizes to "///" which is the equivalent.

Something like "bad://///worse/////" is perfectly valid. Dumb but valid.

Anyway, this answer is not meant to give you the best regex but rather a proof of how to do the string wrapping inside the text, with JavaScript.

OK so lets just use this one: /(https?:\/\/[^\s]+)/g

Again, this is a bad regex. It will have many false positives. However it's good enough for this example.

function urlify(text) {
    var urlRegex = /(https?:\/\/[^\s]+)/g;
    return text.replace(urlRegex, function(url) {
        return '<a href="' + url + '">' + url + '</a>';
    })
    // or alternatively
    // return text.replace(urlRegex, '<a href="$1">$1</a>')
}

var text = "Find me at http://www.example.com and also at http://stackoverflow.com";
var html = urlify(text);

// html now looks like:
// "Find me at <a href="http://www.example.com"&gt;http://www.example.com&lt;/a&gt; and also at <a href="http://stackoverflow.com"&gt;http://stackoverflow.com&lt;/a&gt;"

So in sum try:

$$('#pad dl dd').each(function(element) {
    element.innerHTML = urlify(element.innerHTML);
});