<html xmlns="http://www.w3.org/1999/xhtml"><head></head><body><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="16" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[16]</anchor-end> 
<dfn><sw-cc xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">U+0000</sw-cc></dfn> <dfn><sw-cn xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">NULL</sw-cn></dfn> は、
<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">C0制御文字</anchor>の1つです。</p><section><h1>文脈</h1><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="18" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[18]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">C言語</anchor>では<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">文字列終端</anchor>に使われます (<dfn>NULL終端</dfn>)。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="17" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[17]</anchor-end> <anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">HTMLの構文解析</anchor>では除去されたり <sw-cc xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">U+FFFD</sw-cc> に置き換えられたりします。</p></section><section><h1>関連</h1><p><sw-see xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:"> <anchor>JSON</anchor> </sw-see></p><p><sw-see xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:"> <anchor>文字のセキュリティー</anchor> </sw-see></p></section><section><h1>実出現例</h1><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="15" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[15]</anchor-end> 
<cite>Seznam: TOP.cz</cite>, <time>2025-10-26T06:23:47.000Z</time>, <time>1997-01-10T03:30:18.143Z</time> <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://web.archive.org/web/19970110033017if_/http://www.seznam.cz/nejlepsi.html">https://web.archive.org/web/19970110033017if_/http://www.seznam.cz/nejlepsi.html</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="21" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[21]</anchor-end> <cite>Spotlight</cite>, <time>2025-11-26T08:52:40.000Z</time>, <time>1997-01-17T10:26:32.955Z</time> <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://web.archive.org/web/19970117102437fw_/http://quickdraw3d.apple.com/Spotlight.HTML">https://web.archive.org/web/19970117102437fw_/http://quickdraw3d.apple.com/Spotlight.HTML</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="22" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[22]</anchor-end> <anchor-internal xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="21" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">&gt;&gt;21</anchor-internal> <code>&lt;/table&gt;</code> の後に謎の <sw-cn xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">NULL</sw-cn>。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="23" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[23]</anchor-end> <anchor-internal xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="22" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">&gt;&gt;22</anchor-internal> <cite>Firefox</cite> はソース表示だと <sw-cn xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">NULL</sw-cn> がそのまま <sw-cc xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">U+0000</sw-cc>
で出てくるみたいです。</p></section><section><h1>歴史</h1><section><h1>Web</h1><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="19" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[19]</anchor-end> <cite>Javascriptのprompt関数でユーザー入力を受け付けるとゴミがつく問題</cite>, <time>2020-08-20T23:49:24.000Z</time>, <time>2025-11-23T06:00:55.064Z</time> <anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://www.shtml.jp/mojibake/prompt.html">https://www.shtml.jp/mojibake/prompt.html</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="20" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[20]</anchor-end> <anchor-internal xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="19" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">&gt;&gt;19</anchor-internal> これって実はかなりやばいバグなのでは。。。</p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="3" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[3]</anchor-end> <cite>IRC logs: freenode / #whatwg / 20100715</cite>
(<time>2010-08-03 08:03:40 +09:00</time> 版)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="http://krijnhoetmer.nl/irc-logs/whatwg/20100715">http://krijnhoetmer.nl/irc-logs/whatwg/20100715</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="4" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[4]</anchor-end> <cite>Bug 9659 – Initial U+0000 should not set frameset-ok to &quot;not ok&quot;</cite>
( (<time>2010-10-01 00:32:05 +09:00</time> 版))
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="http://www.w3.org/Bugs/Public/show_bug.cgi?id=9659">http://www.w3.org/Bugs/Public/show_bug.cgi?id=9659</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="5" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[5]</anchor-end> <cite><strong></strong>[<strong></strong>whatwg<strong></strong>]<strong></strong> Null characters</cite>
( (<time>2012-10-09 23:59:44 +09:00</time> 版))
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2012-October/037557.html">http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2012-October/037557.html</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="1" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[1]</anchor-end> <cite xml:lang="en"><strong></strong>[<strong></strong>cssom<strong></strong>]<strong></strong> CSS.escape() U+0000 should be U+FFFD, NOT escaped as code point · w3c/csswg-drafts@061ede6</cite>
(<time>2015-12-07 15:30:13 +09:00</time> 版)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/w3c/csswg-drafts/commit/061ede6cc39156752c9f57494d2d7c8625f4479d">https://github.com/w3c/csswg-drafts/commit/061ede6cc39156752c9f57494d2d7c8625f4479d</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="2" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[2]</anchor-end> <cite xml:lang="en">Re: <strong></strong>[<strong></strong>cssom<strong></strong>]<strong></strong> serializing U+0000 NULL</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Simon Pieters</anchor> 著, <time>2015-11-25 01:19:14 +09:00</time> 版)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://lists.w3.org/Archives/Public/www-style/2015Nov/0322.html">https://lists.w3.org/Archives/Public/www-style/2015Nov/0322.html</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="6" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[6]</anchor-end> <cite xml:lang="en"><strong></strong>[<strong></strong>cssom<strong></strong>]<strong></strong> CSS.escape() serialize U+0000 as \FFFD instead of throwing · w3c/csswg-drafts@c202863</cite>
(<time>2015-12-02 12:30:36 +09:00</time> 版)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/w3c/csswg-drafts/commit/c2028630eaabcd07573ba4df11b8e8ecf653eeaf">https://github.com/w3c/csswg-drafts/commit/c2028630eaabcd07573ba4df11b8e8ecf653eeaf</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="7" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[7]</anchor-end> <cite xml:lang="en"><strong>[</strong>c<strong>]</strong> (0) Make U+0000 characters a parse error.</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2007-06-07 09:40:41 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/ea9371e1f1b9b34f9d9b5473d26aff00f7b26ddd">https://github.com/whatwg/html/commit/ea9371e1f1b9b34f9d9b5473d26aff00f7b26ddd</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="8" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[8]</anchor-end> <cite xml:lang="en"><strong>[</strong>a<strong>]</strong> (0) allow arbitrary characters to be in attribute names; ban U+00…</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2007-06-22 11:20:36 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/09b41b173f9ad59c5677f0ff74c44901962f8ccb">https://github.com/whatwg/html/commit/09b41b173f9ad59c5677f0ff74c44901962f8ccb</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="9" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[9]</anchor-end> <cite xml:lang="en"><strong>[</strong>e<strong>]</strong> (0) Remove the untestable mention of U+0000 in application caches…</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2008-05-08 09:25:55 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/c84521fb373f100e5a771391b3f8205bb64bb154">https://github.com/whatwg/html/commit/c84521fb373f100e5a771391b3f8205bb64bb154</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="10" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[10]</anchor-end> <cite xml:lang="en"><strong>[</strong><strong>]</strong> (0) Revamp how the foreign lands are defined to make it easier to …</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2010-09-30 10:40:08 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/965728b784e9e21826a585dc50dad70488f9ff2a">https://github.com/whatwg/html/commit/965728b784e9e21826a585dc50dad70488f9ff2a</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="11" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[11]</anchor-end> <cite xml:lang="en"><strong>[</strong>giow<strong>]</strong> (2) Parser: don't convert 0000 to FFFD in the input stream pro…</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2010-11-02 11:08:52 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/d98f83e9cfa8c6c365c7ffb34e3dc001a8e4b54c">https://github.com/whatwg/html/commit/d98f83e9cfa8c6c365c7ffb34e3dc001a8e4b54c</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="12" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[12]</anchor-end> <cite xml:lang="en"><strong>[</strong>giow<strong>]</strong> (2) Change how U+0000 NULLs are parsed in MathML text integrat…</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2011-06-15 08:13:39 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/edfa54247249141405e7e812219131f6c4660b90">https://github.com/whatwg/html/commit/edfa54247249141405e7e812219131f6c4660b90</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="13" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[13]</anchor-end> <cite xml:lang="en"><strong>[</strong>e<strong>]</strong> (0) Mention U+0000 handling in the parser.</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">Hixie</anchor>著, <time>2012-12-19 09:33:34 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/098bc56696ad1b9a86a9643e6f7d9e1bc07fada0">https://github.com/whatwg/html/commit/098bc56696ad1b9a86a9643e6f7d9e1bc07fada0</anchor-external></p><p><anchor-end xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:anchor="14" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:">[14]</anchor-end> <cite xml:lang="en">Editorial: use noncharacter and control from Infra</cite>
(<anchor xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:">annevk</anchor>著, <time>2017-04-03 19:40:46 +09:00</time>)
<anchor-external xmlns="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resScheme="URI" xmlns:a0="urn:x-suika-fam-cx:markup:suikawiki:0:9:" a0:resParameter="https://github.com/whatwg/html/commit/70925237a88d9802bfe7224fe9c78b146af615be">https://github.com/whatwg/html/commit/70925237a88d9802bfe7224fe9c78b146af615be</anchor-external></p></section></section></body></html>