gistfile1.js

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

// Wrap the matched strings with `<span class="fake-link"></span>`
$('body').html($('body').html().replace(exp, "<span class='fake-link'>$1</span>"));

$('.fake-link').each(function() {
    // Extra job: Check if parent is an anchor
    if ($(this).parent().is('a')) {
        // If `true`, then unwrap the original anchor which has been written by default from `.fake-link`
        $(this).unwrap();
    }
    // Replace `.fake-link` with an anchor tag
    $(this).replaceWith('<a href="' + $(this).text() + '">' + $(this).text() + '</a>');
});