var bToggle = 0;
function fnToggle() {
    if(navigator.appName == "Microsoft Internet Explorer") document.getElementById('frontImg').filters[0].Apply();                   
// After setting Apply, changes to the oDiv object 
//  are not displayed until Play is called.
	if (bToggle == 0) {
        bToggle++;
        document.getElementById('frontImg').src= "i2.jpg";
	} else if (bToggle == 1) {
		bToggle++;
		document.getElementById('frontImg').src = "i3.jpg";
	} else if (bToggle == 2) {
		bToggle++;
		document.getElementById('frontImg').src = "i4.jpg";
	} else {
		bToggle = 0;
		document.getElementById('frontImg').src = "i1.jpg";
	}
    if(navigator.appName == "Microsoft Internet Explorer") document.getElementById('frontImg').filters[0].Play();
}
setInterval("fnToggle()", 4000);