function newWindow() {

	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") == "new_window")
		anchor.target = "_blank";
	}

}

window.onload = newWindow;