复制代码代码如下：
<html>
<头>
<title>新文档</title>
<meta name =“ generator” content =“ editplus”>
<meta name =“作者” content =“”>
<meta name =“关键字” content =“”>
<meta name =“描述” content =“”>
</head>
<脚本语言=“ javascript”>
函数isReadonly（）{
var obj = document.getElementById（“用户名”）;
obj.setAttribute（“ readonly”，true）;
obj.style.backgroundColor =“＃D2D2D2”;
}
函数readwrite（）{
var obj = document.getElementById（“用户名”）;
obj.setAttribute（“ readonly”，false）;
obj.style.backgroundColor =“＃ffffff”;
}
</script>
<身体>
<form name =“ addform” id =“ addform” method =“ post” action =“”>
<input type =“ text” id =“ username” name =“用户名”>
<input type =“ button” name =“只读”值=“读” onclick =“ isreadonly（）;”>
<input type =“ button” name =“可写” value =“ write” onclick =“ readwrite（）;”>
</form>
</body>
</html>
<！ -
点击“读”按钮，输入框不能书写，且变灰；点击“写”按钮，输入框恢复。
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