用sed删除空行 我的代码如下:class Song def initialize(name) @name = name end def tell puts @name end end class ZhouSong < Song def initialize(name,artist) super(name) @artist = artist end def tell super puts @ar…
在JavaScript中添加以下代码,就可实现 禁用backspace键的后退功能,但是可以删除文本内容 // 禁用backspace键的后退功能,但是可以删除文本内容 document.onkeydown = check; function check(e) { var code; if (!e) var e = window.event; if (e.keyCode) code = e.keyCode; else if (e.which) code = e.which; if (((even…