极客观点
项目管理
HarmonyOS
下面这些代码实在是看不懂，都不知道他正则在那里的作用，有没有大神帮忙注释下，万分感激！！！
// 代码可以直接复制运行（能写这代码的真的是大神啊）：
<!DOCTYPE HTML>
<html>
<head>
<meta charset=UTF-8>
<title>YuGiOh</title>
<style type="text/css">
#div {
position: absolute;
top: 50px;
left: 300px;
width: 300px;
height: 300px;
line-height: 300px;
text-align: center;
border: 1px solid black;
}
</style>
<script type="text/javascript">
var rotateHTML5 = function (limit)
{
var reg = /(rotate\([\-\+]?((\d+)(deg))\))/i;
var wt = div.style['-webkit-transform'], wts = wt.match (reg);
var $2 = RegExp.$2;
console.log ($2);
div.style['-webkit-transform'] = wt.replace ($2, parseFloat (RegExp.$3) + limit + RegExp.$4);
}
var rotateIE = function (obj)
{
var d = !!obj.d ? obj.d : 1;
var r = d * Math.PI / 180;
costheta = Math.cos (r);
sintheta = Math.sin (r);
obj.style.filter = "progid:DXImageTransform.Microsoft.Matrix()";
var item = obj.filters.item (0);
var width = obj.clientWidth;
var height = obj.clientHeight;
item.DX = -width / 2 * costheta + height / 2 * sintheta + width / 2;
item.DY = -width / 2 * sintheta - height / 2 * costheta + height / 2;
item.M11 = costheta;
item.M12 = -sintheta;
item.M21 = sintheta;
item.M22 = costheta;
obj.timer = setTimeout (function ()
{
var dx = d + 1;
dx = dx > 360 ? 1 : dx;
obj.d = dx;
rotate (obj, dx);
}, 30);
};
var start = function ()
{
if (!!div.interval)
{
clearInterval (div.interval);
delete div.interval;
}
else
{
div.interval = setInterval (function ()
{
/.*webkit.*/i.test (navigator.userAgent) ? rotateHTML5 (1) : rotateIE (div);
}, 30);
}
}
</script>
</head>
<body>
<button onclick="start();">rotate</button>
<div id="div" style="border-radius: 90px; -webkit-transform: rotate(10deg);">ROTATE</div>
</body>
</html>
匹配css中
transform:rotate(100deg)
正则作用是提取出100