JavaScript clicks the button on the page, the layer pops up, and the background turns gray_javascript skills

<title>Click the button on the page to pop up a layer and the background turns gray</title> <meta http-equiv="Content-Type " content="text/html; charset=gb2312 "> <p> </p>Click the button on the page to pop up a layer and the background turns gray<input type="button" onclick=" sAlert( '测试效果 嗯！效果还不错！ '); " value="点击这里 "> <input type="button" id="btn" value="test">
[Ctrl A Select all Note:

If you need to introduce external Js, you need to refresh to execute
]Pay attention to style.position and style .zIndex two attributes.