Open Octopress external link in new tab

open-in-blank.js

function addBlankTargetForLinks () {
  $('a[href^="http"]').each(function(){
		$(this).attr('target', '_blank');
	});
}

$(document).bind('DOMNodeInserted', function(event) {
	addBlankTargetForLinks();
});

I did a little change. Only add _blank to those links with no target attribute.
What's more, you should note that jquery is required to make the code running.

$(document).bind('DOMNodeInserted', function(event) {
        $('a[href^="http"]').each(
            function(){
                if (!$(this).attr('target')) {
                    $(this).attr('target', '_blank')
                }

            }
        );
});