[1]
[CITE[Beyond Standards &#8211; Input placeholders]] <http://www.beyondstandards.com/archives/input-placeholders/>

[19] [CITE['''['''whatwg''']''' Question about "Type here your search word(s)" input box]], [TIME[2024-08-20T17:41:27.000Z]], [TIME[2024-09-01T05:08:53.152Z]] <https://lists.whatwg.org/pipermail/whatwg-whatwg.org/2004-July/043097.html>


[2]
[[Web Forms 2.0]] 仕様書の[[注釈宣言]]によれば、
[[Ian Hickson]] は将来の WF への追加の候補として考えているようです。
([[名無しさん]] [WEAK[2006-10-01 08:28:04 +00:00]])

[3] [CITE['''['''whatwg''']''' <textarea placeholder="">]] ([TIME[2009-03-30 19:44:44 +09:00]] 版) <http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-March/019086.html>

[4] [CITE@en[(X)HTML5 Tracking]]
([TIME[2009-08-23 16:05:44 +09:00]] 版)
<http://html5.org/tools/web-apps-tracker?from=2408&to=2409>

[5] [CITE@en[Opera: Opera 11.00 for Windows changelog]]
( ([[Frank M. Palinkas, Technical Writer, Opera Software ASA]] 著, [TIME[2011-04-24 11:17:12 +09:00]] 版))
<http://www.opera.com/docs/changelogs/windows/1100/>

[6] [CITE@en[Web Applications 1.0 r6248     Add placeholder='' support to type=number.]]
( ([TIME[2011-06-17 07:34:00 +09:00]] 版))
<http://html5.org/tools/web-apps-tracker?from=6247&to=6248>

[7] [CITE[IRC logs: freenode / #whatwg / 20110617]]
( ([TIME[2011-06-25 23:12:29 +09:00]] 版))
<http://krijnhoetmer.nl/irc-logs/whatwg/20110617>

[8] [CITE['''['''whatwg''']''' Should editable elements have placeholder attribute?]]
([TIME[2012-06-14 09:13:58 +09:00]] 版)
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2012-June/036391.html>

[9] [CITE@en[:-moz-placeholderから::-moz-placeholderに - fragmentary]]
( ([TIME[2012-11-27 05:02:16 +09:00]] 版))
<http://myakura.hatenablog.com/entry/2012/11/26/224834>

[10] [CITE[''''''[''''''whatwg'''''']'''''' Hide placeholder on input controls on focus]]
( ([TIME[2013-07-30 22:55:12 +09:00]] 版))
<http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2013-July/040300.html>

[11] [CITE[プレースホルダとHTML5のplaceholder属性]]
( ([TIME[2013-03-08 18:31:27 +09:00]] 版))
<http://myakura.github.io/n/placeholder.html>

[12] [CODE(HTMLa)@en[[[placeholder]]]] をラベル代わりに使って、入力すると何の欄だったかわからなくなる糞フォームが溢れて困ったものです。。。

[13] [CITE@en[Web Applications 1.0 r8204      Let's allow newlines in <textarea placeholder=''> after all, since there are some valid use cases.]]
( ([TIME[2013-10-03 03:27:00 +09:00]] 版))
<http://html5.org/tools/web-apps-tracker?from=8203&to=8204>

[14] [CITE@ja[IE10 における placeholder 属性をもつ textarea 要素、または value 属性のない type="checkbox" の input 要素の clone に関するはまりどころ - ひだまりソケットは壊れない]]
( ([TIME[2014-05-02 09:18:24 +09:00]] 版))
<http://vividcode.hatenablog.com/entry/ie10/textarea-placeholder-checkbox-default-value>

[15] [CITE@en[Web Applications 1.0 r8734 Make placeholder='' and autofocus='' work better together]]
( ([TIME[2014-08-30 06:01:00 +09:00]] 版))
<http://html5.org/r/8734>

[16] [CITE@en[Updated placeholder mapping and moved note · w3c/aria@11713b0]]
([TIME[2015-06-16 20:09:11 +09:00]] 版)
<https://github.com/w3c/aria/commit/11713b049c7a6fa559bbab6296a6c24263ae289a>

[17] [CITE@en[Define the :placeholder-shown pseudo-class for HTML elements]]
( ([[SimonSapin]]著, [TIME[2016-06-01 00:43:18 +09:00]]))
<https://github.com/whatwg/html/commit/52d529d35464be2c1a2d2f0d0c0f76d4a49bb9dd>

[18] [CITE@en[12868 – forms: Allow placeholder="" for color and date/time types]]
([TIME[2017-07-23 16:37:08 +09:00]])
<https://www.w3.org/Bugs/Public/show_bug.cgi?id=12868>


[20] 
記入実例だけを [CODE[placeholder]] に使ってるサイトが実際にありますけど、
誤解しか招かないので「例: 」と付けるとかなんか工夫したほうがいいと思います。
[TIME[2024-12-07T07:10:12.300Z]]