function camChange(n) {
	    var sel = document.getElementById('sel'+n);
	    var img = document.getElementById('cam'+n);
	    if (sel && img) {
	        var nocache = "nocache="+(new Date()).getTime();
	        img.src = sel.value + (sel.value.match(/[?]/)?'&':'?') + nocache;
	        setWaitCursor(img,true);
	        return true;
	    } else {
	        return false;
	    }
	}
	function setWaitCursor(e,f) {
	    if (f)
	        e.style.cursor = 'wait';
	    else
	        e.style.cursor = 'default';
	}
	function update() {
	    var n = 0;
	    while(camChange(n)) n++;
	}
	function pageLoaded() {
	    window.setInterval("update();",180000);
	}