<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
html{
filter: grayscale(100%);
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale (100%);
filter:progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
}
</style>
</head>
<body>
<img src="aaa.jpg">
</body>
</html>
Effect picture: