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;