文本框内容禁止复制粘贴效果
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html;charset=gb2312">
<title>hello</title>
</head>
<body>
<a href="www.baidu.com/">百度</a>hello welcome。<hr>
<input type="text" id="username" name="username" value="hello welcome！" onpaste="return false" oncontextmenu="return false" oncopy="return false" oncut="return false">
</body>
</html>
