add target=_blank to all external links on a site

external links

 function externalLinks() {
	var url_test = false;
 	var anchors = document.getElementsByTagName("a");
  	for (var i=anchors.length; i>=0; i--) {
  		var anchor = anchors[i];
    	anchor_url = encodeURI(anchor);
		url_test = /baynature/.test(anchor_url);
		// baynature is the name of the site
		if (url_test == false){
			if (anchor_url != "undefined"){
//not sure where the undefined was coming from, but showed up as first anchor tag on site
				anchor.target = "_blank";
			}
		}
	}
}
  window.onload = externalLinks;