<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title> ImageRotation </title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
#demo { cursor:pointer; position:absolute;filter:progid:DXImageTransform.Microsoft.Matrix(sizingmethod="auto expand");}
</style>
</head>
<body>
<div id="container" style="width:500px;height:350px;position:relative;margin:0 auto">
<div id="demo">
<img src="http://images.cnblogs.com/cnblogs_com/bluedream2009/201609/o_mm.jpg" width="500" height="333" />
</div>
</div>
<script>
var Img = function() {
var T$ = function(id) { return document.getElementById(id); }
var ua = navigator.userAgent,
isIE = /msie/i.test(ua) && !window.opera;
var i = 0, sinDeg = 0, cosDeg = 0, timer = null ;
var rotate = function(target, degree) {
target = T$(target);
var orginW = target.clientWidth, orginH = target.clientHeight;
clearInterval(timer);
function run(angle) {
if (isIE) { // IE
cosDeg = Math.cos(angle * Math.PI / 180);
sinDeg = Math.sin(angle * Math.PI / 180);
with(target.filters.item(0)) {
M11 = M22 = cosDeg; M12 = -(M21 = sinDeg);
}
target.style.top = (orginH - target.offsetHeight) / 2 + 'px';
target.style.left = (orginW - target.offsetWidth) / 2 + 'px';
} else if (target.style.MozTransform !== undefined) { // Mozilla
target.style.MozTransform = 'rotate(' + angle + 'deg)';
} else if (target.style.OTransform !== undefined) { // Opera
target.style.OTransform = 'rotate(' + angle + 'deg)';
} else if (target.style.webkitTransform !== undefined) { // Chrome Safari
target.style.webkitTransform = 'rotate(' + angle + 'deg)';
} else {
target.style.transform = "rotate(" + angle + "deg)";
}
}
timer = setInterval(function() {
i += 10;
run(i);
if (i > degree - 1) {
i = 0;
clearInterval(timer);
}
}, 10);
}
return {rotate: rotate}
}();
window.onload = function() {
Img.rotate('demo', 360);
document.getElementById('demo').onclick = function() {
Img.rotate('demo', 360);
}
}
</script>
</body>
</html>
这是在网上找的一段代码,完全不明白,谁能讲解一下它的原理,以及上面的代码,谢谢了