var iSecondsToUpdateWebCamImg = 4; //seconds
var iCount = 0;

var timerUpdateWebCamImg = setInterval('updateWebCamImg()', iSecondsToUpdateWebCamImg * 1000);
function updateWebCamImg(){
	var imgWebCam = document.getElementById('imgWebCam');	
	if (imgWebCam){
		var dNow = new Date();
		imgWebCam.src = 'http://www.dirty-paper.com/webcam/ccam.jpg?' + iCount + '-' + dNow.getTime();
		iCount++
		if (document.getElementById('divCounter')){
			document.getElementById('divCounter').innerHTML = iCount
		}
	}
}