function classTags() {  
	if (document.getElementsByTagName) {  
		var anchors = document.getElementsByTagName( "a" );  
		for (var loop = 0; loop < anchors.length; loop++) {  
			var anchor = anchors[loop];  
			if (anchor.getAttribute("href") && anchor.getAttribute("class") == "external") {  
			anchor.target = "external";  
			}  
		}  
	}  
}  

window.onload = function() {  
	classTags();  
}