sfHover = function() {
	var sfEls = document.getElementById("navbar").getElementsByTagName("li");
	for (var i=0; i<sfEls.length; i++) {
		sfEls[i].onmouseover=function() {
			this.className+=" hover";
		}
		sfEls[i].onmouseout=function() {
			this.className=this.className.replace(new RegExp(" hover\\b"), "");
		}
	}
}
if (window.attachEvent) window.attachEvent("onload", sfHover);




<!-- hide from none JavaScript Browsers
Image1= new Image(56,60)
Image1.src = "images/left_case_hover.gif"
Image2 = new Image(56,60)
Image2.src = "images/case_studies_left.gif"

function Frown() {
document.imagefliper.src = Image1.src; return true;
}

function Smile() {
document.imagefliper.src = Image2.src; return true;
}


Image3= new Image(64,68)
Image3.src = "images/right_hover_case.gif"
Image4 = new Image(64,68)
Image4.src = "images/case_studies_right.gif"

function Firsti() {
document.imagefliper2.src = Image3.src; return true;
}

function Secondi() {
document.imagefliper2.src = Image4.src; return true;
}

<!-- hide from none JavaScript Browsers
Image5= new Image(56,60)
Image5.src = "images/left_case_hover.gif"
Image6 = new Image(56,60)
Image6.src = "images/case_studies_left.gif"

function Thirdi() {
document.imagefliper5.src = Image1.src; return true;
}

function Fourthi() {
document.imagefliper5.src = Image2.src; return true;
}


Image7= new Image(64,68)
Image7.src = "images/right_hover_case.gif"
Image8 = new Image(64,68)
Image8.src = "images/case_studies_right.gif"

function Fifthi() {
document.imagefliper6.src = Image3.src; return true;
}

function Sixti() {
document.imagefliper6.src = Image4.src; return true;
}


// - stop hiding -->