Using jQuery to check if a link is internal or external

Question

I want to write a script which can determine whether a link is internal or external. This is simple from my perspective, all internal links are relative, so they start with

Answer 1

I use this one to find all urls pointing to domain other than current domain or one with (html5 deprecated) attribute target="_blank"

var contrastExternalLinks =  function() {
    //create a custom external selector for finding external links
    $.expr[':'].external = function( obj ) {
        return (
            $(obj).attr('target')   &&  $(obj).attr('target') =='_blank' ) 
                || 
                    (!obj.href.match(/^mailto\:/)   && !obj.href.match(/^tel\:/)    &&  (obj.hostname != location.hostname )
                        );
    };
    // Usage:
    $(document).ready(function() {
        $('a:external').addClass('external');///css('background-color', 'green');   
    })



}();