<html>
<head>
<title>wheeltest4.htm</title>
<script type="text/javascript">
var clicks = 0;
var zoom = 0;
var zoomString = "<br>";
var certainInterval = 0.3;
var deltaNum = 0.0;
var timeStart = 0.0;
var timeStop = 0.0;
var difference = 0.0;
function getTimeNow() {
if (newDate != null) {
newDate = null;
}
var newDate = new Date();
return newDate.valueOf();
}
function handle(delta) {
if (clicks % 2 != 0) {
timeStart = getTimeNow();
} else {
timeStop = getTimeNow();
difference = timeStop - timeStart;
}
var s = delta + ": ";
if (delta < 0) {
zoom--;
s += "down";
} else {
zoom++;
s += "up";
}
// Here, assume we do not want any value to go outside the range -14 to 14.
if (zoom > 14) {
zoom = 14;
}
if (zoom < -14) {
zoom = -14;
}
// If there were wheel events with at least certain interval (eg, 0.5), then record it in zoomString.
if (difference/1000 >= certainInterval) {
zoomString += "<br>" + zoom;
}
document.getElementById('delta').innerHTML = s + "<br>current zoom: " + zoom + "<br>" + zoomString + "<br>clicks: " + clicks;
clicks++;
}
function wheel(event){
if (!event) {
event = window.event;
}
if (event.wheelDelta) {
deltaNum = event.wheelDelta/120;
if (window.opera) {
deltaNum = -deltaNum;
}
} else if (event.detail) {
deltaNum = -event.detail/3;
}
if (deltaNum) {
handle(deltaNum);
}
}
/* Initialization code. */
if (window.addEventListener) {
window.addEventListener('DOMMouseScroll', wheel, false);
}
window.onmousewheel = document.onmousewheel = wheel;
</script>
</head>
<body>
<div id="delta">Scroll mouse wheel to see delta here.</div>
</body>
</html>