<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
ImageRotation
#demo { cursor:pointer; position:absolute;filter:progid:DXImageTransform.Microsoft.Matrix(sizingmethod="auto expand");}
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);
}
}
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
