// Thanks to SitePoint
// http://articles.sitepoint.com/article/standards-compliant-world

function externalLinks()
{
	if(!document.getElementsByTagName)
	{
		return;
	}

	var anchors = document.getElementsByTagName("a");
 
	for (var i = 0; i < anchors.length; i++)
	{   
		var anchor = anchors[i];
		if(anchor.getAttribute("href") && anchor.getAttribute("rel") == "external")
		{
			anchor.target = "_blank";
		}
	}
}

window.onload = externalLinks;