$.extend({	
		aTag:function(c){
			/** add target="_blank" to all external location **/
			if(c.e){
				$(c.c).filter(function(){
					return this.hostname && this.hostname !== location.hostname;
				}).addClass('external').attr('target', '_blank');
			}
			
		}	
	})
		
	$(document).ready(function(){
		$.aTag({c: "#article a", e: true});
		$.leftNavigation('#left-navigation');
	});