コメント欄にタグ<～>があると表示に問題が生じるので<～>に置換してから書くことにしていて、そのためのWebページを作って #Javascript に次のコードを入れてある。
str = str.replace(/</g,"&"+"lt;");問題なく動作するのだけど、HTML4.01での次の注意が気になる。
B.3.2 Specifying non-HTML data
Script and style data may appear as element content or attribute values. The following sections describe the boundary between HTML markup and foreign data.
Note. The DTD defines script and style data to be CDATA for both element content and attribute values. SGML rules do not allow character references in CDATA element content but do allow them in CDATA attribute values. Authors should pay particular attention when cutting and pasting script and style data between element content and attribute values.
This asymmetry also means that when transcoding from a richer to a poorer character encoding, the transcoder cannot simply replace unconvertible characters in script or style data with the corresponding numeric character references; it must parse the HTML document and know about each script and style language's syntax in order to process the data correctly.
Element contentWhen script or style data is the content of an element (SCRIPT and STYLE), the data begins immediately after the element start tag and ends at the first ETAGO ("</") delimiter followed by a name start character ([a-zA-Z]); note that this may not be the element's end tag. Authors should therefore escape "</" within the content. Escape mechanisms are specific to each scripting or style sheet language.
Performance, Implementation, and Design Notes
https://www.w3.org/TR/html401/appendix/notes.html#h-B.3.2
#Javascript 内に"</"を書いてはいけないらしい。でも、次の置換のためのコードには含まれてる。
str = str.replace(/</g,"&"+"lt;");#Gemini に相談したのだけど、"</"が含まれるのを避ける方法は見つからなかった。
ちなみに、今はHTML4.01ではない。HTML5でもダメらしいが、今はHTML5でもないはず。
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