if (document.styleSheets && document.styleSheets.length > 0) {  
		    var ss = document.styleSheets[0];  
		    var bRule = (ss.cssRules ? ss.cssRules : ss.rules);  
		    if (bRule.length > 1) {  
		        bRule[0].style.display = "block";  
		        bRule[1].style.display = "none";  
		    }  
		}