HTML5 textarea占位符没有出现 [英] HTML5 textarea placeholder not appearing
问题描述
我不知道我的标记有什么问题，但是文本区域的占位符不会出现.似乎它可能被一些空格和制表符掩盖了.当您关注文本区域并从光标所在的位置删除时，然后离开文本区域，相应的占位符就会出现.
I cannot figure out what is wrong with my markup, but the placeholder for the text area will not appear. It seems as though it may be covered up with some blank spaces and tabs. When you focus on the text area and delete from where the cursor puts itself, then leave the text area, the proper placeholder then appears.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
</head>
<body>
<form action="message.php" method="post" id="message_form">
<fieldset>
<input type="email" name="email" id="email" title="Email address"
maxlength="40"
placeholder="Email Address"
autocomplete="off" required />
<br />
<input type="text"
name="subject"
id="subject" title="Subject"
maxlength="60" placeholder="Subject" autocomplete="off" required />
<br />
<textarea name="message"
id="message"
title="Message"
cols="30"
rows="5"
maxlength="100"
placeholder="Message" required>
</textarea>
<br />
<input type="submit" value="Send" id="submit"/>
</fieldset>
</form>
</body>
<script>
$(document).ready(function() {
$('#message_form').html5form({
allBrowsers : true,
responseDiv : '#response',
messages: 'en',
messages: 'es',
method : 'GET',
colorOn :'#d2d2d2',
colorOff :'#000'
}
);
});
</script>
</html>
推荐答案
这个方案对我和其他许多人来说一直是个难题.总之，<textarea>元素的开始和结束标签必须在同一行，否则换行符占据了它.由于输入区域包含内容(换行符在技术上是有效的内容)，因此不会显示占位符.
This one has always been a gotcha for me and many others. In short, the opening and closing tags for the <textarea> element must be on the same line, otherwise a newline character occupies it. The placeholder will therefore not be displayed since the input area contains content (a newline character is, technically, valid content).
好:
<textarea></textarea>
不好:
<textarea>
</textarea>
更新(2020 年)
这是不正确 不再，根据 HTML5 解析规范:
Update (2020)
This is not true anymore, according to the HTML5 parsing spec:
If the next token is a U+000A LINE FEED (LF) character token,
then ignore that token and move on to the next one. (Newlines
at the start of textarea elements are ignored as an authoring
convenience.)
不过，如果您的编辑坚持使用 CRLF 结束行，您可能仍然会遇到问题.
You might still have trouble if you editor insists on ending lines with CRLF, though.
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