How to replace plain URLs with links?

Replacing URLs with links (Answer to the General Problem)

The regular expression in the question misses a lot of edge cases. When detecting URLs, it's always better to use a specialized library that handles international domain names, new TLDs like .museum, parentheses and other punctuation within and at the end of the URL, and many other edge cases. See the Jeff Atwood's blog post The Problem With URLs for an explanation of some of the other issues.

The best summary of URL matching libraries is in Dan Dascalescu's Answer
(as of Feb 2014)

"Make a regular expression replace more than one match" (Answer to the specific problem)

Add a "g" to the end of the regular expression to enable global matching:

/ig;

But that only fixes the problem in the question where the regular expression was only replacing the first match. Do not use that code.

Thanks, this was very helpful. I also wanted something that would link things that looked like a URL -- as a basic requirement, it'd link something like www.yahoo.com, even if the http:// protocol prefix was not present. So basically, if "www." is present, it'll link it and assume it's http://. I also wanted emails to turn into mailto: links. EXAMPLE: www.yahoo.com would be converted to www.yahoo.com

Here's the code I ended up with (combination of code from this page and other stuff I found online, and other stuff I did on my own):

function Linkify(inputText) {
    //URLs starting with http://, https://, or ftp://
    var replacePattern1 = /(\b(https?|ftp):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/gim;
    var replacedText = inputText.replace(replacePattern1, '<a href="$1" target="_blank">$1</a>');

    //URLs starting with www. (without // before it, or it'd re-link the ones done above)
    var replacePattern2 = /(^|[^\/])(www\.[\S]+(\b|$))/gim;
    var replacedText = replacedText.replace(replacePattern2, '$1<a href="http://$2" target="_blank">$2</a>');

    //Change email addresses to mailto:: links
    var replacePattern3 = /(\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,6})/gim;
    var replacedText = replacedText.replace(replacePattern3, '<a href="mailto:$1">$1</a>');

    return replacedText
}

In the 2nd replace, the (^|[^/]) part is only replacing www.whatever.com if it's not already prefixed by // -- to avoid double-linking if a URL was already linked in the first replace. Also, it's possible that www.whatever.com might be at the beginning of the string, which is the first "or" condition in that part of the regex.

This could be integrated as a jQuery plugin as Jesse P illustrated above -- but I specifically wanted a regular function that wasn't acting on an existing DOM element, because I'm taking text I have and then adding it to the DOM, and I want the text to be "linkified" before I add it, so I pass the text through this function. Works great.

/**
 * Convert URLs in a string to anchor buttons
 * @param {!string} string
 * @returns {!string}
 */

function URLify(string){
  var urls = string.match(/(((ftp|https?):\/\/)[\-\w@:%_\+.~#?,&\/\/=]+)/g);
  if (urls) {
    urls.forEach(function (url) {
      string = string.replace(url, '<a target="_blank" href="' + url + '">' + url + "</a>");
    });
  }
  return string.replace("(", "<br/>(");
}

simple example

Try the below function :

function anchorify(text){
  var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
  var text1=text.replace(exp, "<a href='$1'>$1</a>");
  var exp2 =/(^|[^\/])(www\.[\S]+(\b|$))/gim;
  return text1.replace(exp2, '$1<a target="_blank" href="http://$2">$2</a>');
}

alert(anchorify("Hola amigo! https://www.sharda.ac.in/academics/"));

I had to do the opposite, and make html links into just the URL, but I modified your regex and it works like a charm, thanks :)

var exp = /<a\s.*href=['"](\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])['"].*>.*<\/a>/ig;

source = source.replace(exp,"$1");

The e-mail detection in Travitron's answer above did not work for me, so I extended/replaced it with the following (C# code).

// Change e-mail addresses to mailto: links.
const RegexOptions o = RegexOptions.Multiline | RegexOptions.IgnoreCase;
const string pat3 = @"([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,6})";
const string rep3 = @"<a href=""mailto:$1@$2.$3"">$1@$2.$3</a>";
text = Regex.Replace(text, pat3, rep3, o);

This allows for e-mail addresses like "firstname.secondname@one.two.three.co.uk".

After input from several sources I've now a solution that works well. It had to do with writing your own replacement code.

Answer.

Fiddle.

function replaceURLWithHTMLLinks(text) {
    var re = /(\(.*?)?\b((?:https?|ftp|file):\/\/[-a-z0-9+&@#\/%?=~_()|!:,.;]*[-a-z0-9+&@#\/%=~_()|])/ig;
    return text.replace(re, function(match, lParens, url) {
        var rParens = '';
        lParens = lParens || '';

        // Try to strip the same number of right parens from url
        // as there are left parens.  Here, lParenCounter must be
        // a RegExp object.  You cannot use a literal
        //     while (/\(/g.exec(lParens)) { ... }
        // because an object is needed to store the lastIndex state.
        var lParenCounter = /\(/g;
        while (lParenCounter.exec(lParens)) {
            var m;
            // We want m[1] to be greedy, unless a period precedes the
            // right parenthesis.  These tests cannot be simplified as
            //     /(.*)(\.?\).*)/.exec(url)
            // because if (.*) is greedy then \.? never gets a chance.
            if (m = /(.*)(\.\).*)/.exec(url) ||
                    /(.*)(\).*)/.exec(url)) {
                url = m[1];
                rParens = m[2] + rParens;
            }
        }
        return lParens + "<a href='" + url + "'>" + url + "</a>" + rParens;
    });
}

Here's my solution:

var content = "Visit https://wwww.google.com or watch this video: https://www.youtube.com/watch?v=0T4DQYgsazo and news at http://www.bbc.com";
content = replaceUrlsWithLinks(content, "http://");
content = replaceUrlsWithLinks(content, "https://");

function replaceUrlsWithLinks(content, protocol) {
    var startPos = 0;
    var s = 0;

    while (s < content.length) {
        startPos = content.indexOf(protocol, s);

        if (startPos < 0)
            return content;

        let endPos = content.indexOf(" ", startPos + 1);

        if (endPos < 0)
            endPos = content.length;

        let url = content.substr(startPos, endPos - startPos);

        if (url.endsWith(".") || url.endsWith("?") || url.endsWith(",")) {
            url = url.substr(0, url.length - 1);
            endPos--;
        }

        if (ROOTNS.utils.stringsHelper.validUrl(url)) {
            let link = "<a href='" + url + "'>" + url + "</a>";
            content = content.substr(0, startPos) + link + content.substr(endPos);
            s = startPos + link.length;
        } else {
            s = endPos + 1;
        }
    }

    return content;
}

function validUrl(url) {
    try {
        new URL(url);
        return true;
    } catch (e) {
        return false;
    }
}

Try Below Solution

function replaceLinkClickableLink(url = '') {
let pattern = new RegExp('^(https?:\\/\\/)?'+
        '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.?)+[a-z]{2,}|'+
        '((\\d{1,3}\\.){3}\\d{1,3}))'+
        '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+
        '(\\?[;&a-z\\d%_.~+=-]*)?'+
        '(\\#[-a-z\\d_]*)?$','i');

let isUrl = pattern.test(url);
if (isUrl) {
    return `<a href="${url}" target="_blank">${url}</a>`;
}
return url;
}

worked for me :

var urlRegex =/(\b((https?|ftp|file):\/\/)?((([a-z\d]([a-z\d-]*[a-z\d])*)\.)+[a-z]{2,}|((\d{1,3}\.){3}\d{1,3}))(\:\d+)?(\/[-a-z\d%_.~+]*)*(\?[;&a-z\d%_.~+=-]*)?(\#[-a-z\d_]*)?)/ig;

return text.replace(urlRegex, function(url) {
    var newUrl = url.indexOf("http") === -1 ? "http://" + url : url;
    return '<a href="' + newUrl + '">' + url + '</a>';
});