&Required — always escape bare & in HTML
<Required — prevents tag confusion
>Good practice in attribute values
"Use inside attribute values
Non-breaking space — prevents line breaks
©Copyright symbol in footers
—Em dash for parenthetical statements
…Ellipsis for truncated text
HTMLエンティティは、HTMLで予約済みまたは特殊な文字を表すために使用される特殊なコードです。&で始まり;で終わります。例えば、&amp;は&を、&lt;は<を表します。
HTML予約文字（< > & "）にはHTMLエンティティを使用します。その他の記号にはUnicode（&#...;）の方が移植性が高く、現代のブラウザで広くサポートされています。
&copy;のような名前付きエンティティは人間が読みやすいですが、すべての文字に名前があるわけではありません。数値エンティティはどのUnicode文字にも使用できます（10進数：© または16進数：©）。
&amp;を使って&を表示します。HTMLの属性やコンテンツで裸の&を使用しないでください——解析エラーを引き起こす可能性があります。
| 文字 | エンティティ | 説明 |
|---|---|---|
| & | Ampersand | |
| < | Less-than sign | |
| > | Greater-than sign | |
| " | Quotation mark | |
| ' | Apostrophe | |
| Non-breaking space | ||
| | Soft hyphen | |
| | — | Zero Width Joiner |
| — | Em dash | |
| – | En dash | |
| … | Horizontal ellipsis | |
| « | Left double angle quotation | |
| » | Right double angle quotation | |
| ‘ | Left single quotation mark | |
| ’ | Right single quotation mark | |
| “ | Left double quotation mark | |
| ” | Right double quotation mark | |
| · | Middle dot | |
| • | Bullet | |
| ‣ | — | Triangular bullet |
| © | Copyright sign | |
| ® | Registered sign | |
| ™ | Trade mark sign | |
| ℠ | — | Service mark |
| ° | Degree sign | |
| § | Section sign | |
| ¶ | Pilcrow (paragraph) | |
| † | Dagger | |
| ‡ | Double dagger | |
| ★ | — | Black star |
| ☆ | — | White star |
| ♥ | Black heart suit | |
| ♦ | Black diamond suit | |
| ♠ | Black spade suit | |
| ♣ | Black club suit | |
| ✓ | — | Check mark |
| ✗ | — | Ballot X |
| ∞ | Infinity | |
| ‰ | Per mille sign | |
| + | — | Plus sign |
| − | Minus sign | |
| × | Multiplication sign | |
| ÷ | Division sign | |
| = | — | Equals sign |
| ≠ | Not equal to | |
| ≈ | Almost equal to | |
| ≡ | Identical to | |
| ≤ | Less than or equal to | |
| ≥ | Greater than or equal to | |
| ± | Plus-minus sign | |
| √ | Square root | |
| ∑ | N-ary summation | |
| ∏ | N-ary product | |
| π | Greek small letter pi | |
| ½ | Vulgar fraction one-half | |
| ¼ | Vulgar fraction one-quarter | |
| ¾ | Vulgar fraction three-quarters | |
| ² | Superscript two | |
| ³ | Superscript three | |
| ← | Leftwards arrow | |
| → | Rightwards arrow | |
| ↑ | Upwards arrow | |
| ↓ | Downwards arrow | |
| ↔ | Left right arrow | |
| ↕ | — | Up down arrow |
| ⇐ | Leftwards double arrow | |
| ⇒ | Rightwards double arrow | |
| ⇑ | Upwards double arrow | |
| ⇓ | Downwards double arrow | |
| ⇔ | Left right double arrow | |
| ↩ | — | Leftwards arrow with hook |
| ↪ | — | Rightwards arrow with hook |
| ↺ | — | Anticlockwise open circle arrow |
| ↻ | — | Clockwise open circle arrow |
| $ | — | Dollar sign |
| € | Euro sign | |
| £ | Pound sign | |
| ¥ | Yen sign | |
| ¢ | Cent sign | |
| ₿ | — | Bitcoin sign |
| ₹ | — | Indian rupee sign |
| ₩ | — | Won sign |
| ¤ | Currency sign | |
| À | A with grave | |
| Á | A with acute | |
| Â | A with circumflex | |
| Ã | A with tilde | |
| Ä | A with diaeresis | |
| Å | A with ring above | |
| Æ | AE ligature | |
| Ç | C with cedilla | |
| È | E with grave | |
| É | E with acute | |
| Ñ | N with tilde | |
| Ö | O with diaeresis | |
| Ü | U with diaeresis | |
| ß | Sharp s (eszett) | |
| à | a with grave | |
| á | a with acute | |
| â | a with circumflex | |
| ã | a with tilde | |
| ä | a with diaeresis | |
| å | a with ring above | |
| æ | ae ligature | |
| ç | c with cedilla | |
| è | e with grave | |
| é | e with acute | |
| ñ | n with tilde | |
| ö | o with diaeresis | |
| ü | u with diaeresis | |
| ø | o with stroke (slash) | |
| Ø | O with stroke (slash) |