This does not work with IE7: [js]elem.setAttribute(‘class’, cssClass);[/js] Use this instead: [js]elem.setAttribute((document.all ? ‘className’ : ‘class’), cssClass);[/js] Problem: document.all exists in IE8 too, but IE8 does not work with ‘className’! My solution in one of my projects was prototype: [js]Prototype.Browser.IE6 = Prototype.Browser.IE && parseInt(navigator.userAgent.substring(navigator.userAgent.indexOf("MSIE")+5)) == 6; Prototype.Browser.IE7 = Prototype.Browser.IE && parseInt(navigator.userAgent.substring(navigator.userAgent.indexOf("MSIE")+5)) == 7; Prototype.Browser.IE8 = Prototype.Browser.IE && !Prototype.Browser.IE6 && !Prototype.Browser.IE7; …