How to find if a text contains url string

Question

How can I find if text contains a url string. I mean if I have

Sometexthttp://daasddas some text

I want http://daasddas to be achored or maked as a link wit javascript

Answer 1

    function replaceURLWithHTMLLinks(text)
    {
      var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
      return text.replace(exp,"<a href='$1'>$1</a>"); 
    }

Answer 2

While the code above works good if all given URLs are full (http://mydomain.com), I had problems parsing a URL like:

www.mydomain.com

i.e. without a protocol. So I added some simple code to the function:

var exp = /(\b(((https?|ftp|file|):\/\/)|www[.])[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
var temp = text.replace(exp,"<a href=\"$1\" target=\"_blank\">$1</a>");
var result = "";

while (temp.length > 0) {
    var pos = temp.indexOf("href=\"");
    if (pos == -1) {
        result += temp;
        break;
    }
    result += temp.substring(0, pos + 6);

    temp = temp.substring(pos + 6, temp.length);
    if ((temp.indexOf("://") > 8) || (temp.indexOf("://") == -1)) {
        result += "http://";
    }
}

return result;

If someone should fine a more optimal solution to add a default protocol to URLs, let me know!

Answer 3

I tweaked dperinis regex-url script so that a URL embedded in a string can be found. It will not find google.com, this is necessary if it's a user input field, the user might leave out the whitespace after a period/full stop. It will also find www.google.com, since hardly anyone types the protocol.

(?:((?:https?|ftp):\/\/)|ww)(?:\S+(?::\S*)?@)?(?:(?!(?:10|127)(?:\.\d{1,3}){3})(?!(?:169\.254|192\.168)(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*(?:\.(?:[a-z\u00a1-\uffff]{2,}))\.?)(?::\d{2,5})?(?:[/?#]\S*)?

I tested it on www.regextester.com, it worked for me, if you encounter a problem, please comment.

Answer 4

You have to use regex(Regular expressions) to find URL patterns in blocks of text.

Here's a link to same question and answers: Regular Expression to find URLs in block of Text (Javascript)

Answer 5

Many of the solutions start getting very complex and hard to work with a variety of situations. Here's a function I created to capture any URL beginning with http/https/ftp/file/www. This is working like a charm for me, the only thing it doesn't add a link to is user entered URL's without an http or www at the beginning (i.e. google.com). I hope this solution is helpful for somebody.

function convertText(txtData) {
    var urlRegex =/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
    txtData = txtData.replace(urlRegex, '<a href="$1">$1</a>');

    var urlRegex =/(\b(\swww).[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
    txtData = txtData.replace(urlRegex, ' <a href="$1">$1</a>');

    var urlRegex =/(>\swww)/ig;
    txtData = txtData.replace(urlRegex, '>www');

    var urlRegex =/(\"\swww)/ig;
    txtData = txtData.replace(urlRegex, '"http://www');

    return txtData;
}

Answer 6

  function replaceURLWithHTMLLinksHere(text)
  {
    var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
    return text.replace(exp,"<a href='$1'>$1</a>"); 
   }

Okay we got this regular expresion here in function.

/(\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~|!:,.;]*[-A-Z0-9+&@#/%=~|])/ig

Lets understand this.

/ / this is how a regex starts.

\b > is maching https or ftp or file that is unique and is in the start of string. these keywords should not have any character attatched to them in begining like bbhttps or bbhttp it will not match these otherwise.

https? > here ? means zero or one of preceding character or group. In this case s is optional.

| > match one out of given just like OR.

() > create group to be matched

/ > means the next character is special and is not to be interpreted literally. For example, a 'b' without a preceding '\' generally matches lowercase 'b's wherever they occur. But a '\b' by itself doesn't match any character

[] > this is Character Classes or Character Sets. It is used to have a group of characters and only one character out of all will be present at a time.

[-A-Z0-9+&@#/%?=~_|!:,.;]* > zero or more occurrences of the preceding element. For example, b*c matches "c", "bc", "bbc", "bbbc", and so on.

[-A-Z0-9+&@#/%=~_|] > means one charactor out of these all.

i > Case-insensitive search. g > Global search.

Answer 7

you can use a regular expression to find an URL and replace it by the same with a leading and a trailing tag

Answer 8

function replaceURLWithLinks(text){
    var text = "";
    text= text.replace(/\r?\n/g, '<br />');
    var result = URI.withinString(text, function(url) {
        return "<a href='"+url+"' target='_blank'>" + url + "</a>";
    });
}