<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title></title>
<script src="jquery-1.7.1.min.js"></script>
<script>
$(function () {
$(btn).click(function () {
if (this.value == '关灯') {
$('body').css('background-color', 'black');
$(this).val('开灯');
} else {
$('body').css('background-color', 'white');
$(this).val('关灯');
}
});
});
</script>
</head>
<body>
<input type="button" name="name" value="关灯" id="btn" />
</body>
</html>
