複製代碼代碼如下：
<html>
<頭>
<title>新文檔</title>
<meta name =“ generator” content =“ editplus”>
<meta name =“作者” content =“”>
<meta name =“關鍵字” content =“”>
<meta name =“描述” content =“”>
</head>
<腳本語言=“ javascript”>
函數isReadonly（）{
var obj = document.getElementById（“用戶名”）;
obj.setAttribute（“ readonly”，true）;
obj.style.backgroundColor =“＃D2D2D2”;
}
函數readwrite（）{
var obj = document.getElementById（“用戶名”）;
obj.setAttribute（“ readonly”，false）;
obj.style.backgroundColor =“＃ffffff”;
}
</script>
<身體>
<form name =“ addform” id =“ addform” method =“ post” action =“”>
<input type =“ text” id =“ username” name =“用戶名”>
<input type =“ button” name =“只讀”值=“讀” onclick =“ isreadonly（）;”>
<input type =“ button” name =“可寫” value =“ write” onclick =“ readwrite（）;”>
</form>
</body>
</html>
<！ -
點擊“讀”按鈕，輸入框不能書寫，且變灰；點擊“寫”按鈕，輸入框恢復。
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