$(document).ready(function() {
    // Creating custom :external selector
    $.expr[':'].external = function(obj){
        return !obj.href.match(/^mailto\:/) && (obj.hostname.replace(/\:\d+$/,'') != location.hostname);
    };
    
    // Add 'external' CSS class to all external links
    $('a:external').addClass('external').attr('target', '_blank');
});