function external() {
	if (document.getElementsByTagName) {
		var i, a, t;
		a = document.getElementsByTagName('a');
		t = a.length-1;
		for (i=0; i<=t; i++) {
			if(a[i]){
				if (a[i].getAttribute('href') && a[i].getAttribute('rel') == 'external'){
					a[i].target = '_blank';
					}
				}
			}
		}
	}

window.onload = external;