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;