https://blog.csdn.net/u010849590/article/details/43380181
HTML开发特殊字符是没办法原样输出的，必须用到实体，为了以后查看方便，收藏一下实体对照表是必要的，另外，使用<xmp></xmp>标签可以原样输出，当然，也包括特殊字符啦！
实体参考（摘抄至网络）
| 字符 | 数字参考 | 实体参考 | 描述 |
| " | " | " | Quotation mark |
| & | & | & | Ampersand |
| < | < | < | Less than |
| > | > | > | Greater than |
| (空白) |   | | Non-breaking space |
| ¡ | ¡ | ¡ | Inverted exclamation |
| ¢ | ¢ | ¢ | Cent sign |
| £ | £ | £ | Pound sterling |
| ¤ | ¤ | ¤ | General currency sign |
| ¥ | ¥ | ¥ | Yen sign |
| ¦ | ¦ | ¦ | broken vertical bar |
| § | § | § | Section sign |
| ¨ | ¨ | ¨ | Diæresis / umlaut |
| © | © | © | Copyright |
| ª | ª | ª | Feminine ordinal |
| « | « | « | Left angle quote |
| ¬ | ¬ | ¬ | Not sign |
| ­ | &sny; | Soft hyphen | |
| ® | ® | ® | Registered trademark |
| ¯ | ¯ | ¯ | Macron accent |
| ° | ° | ° | Degree sign |
| ± | ± | ± | Plus or minus |
| ² | ² | ² | Superscript two |
| ³ | ³ | ³ | Superscript three |
| ´ | ´ | ´ | Acute accent |
| µ | µ | µ | Micro sign |
| ¶ | ¶ | ¶ | Paragraph sign |
| · | · | · | Middle dot |
| ¸ | ¸ | ¸ | Cedilla |
| ¹ | ¹ | &supl; | Superscript one |
| º | º | º | Masculine ordinal |
| » | » | » | Right angle quote |
| ¼ | ¼ | ¼ | Fraction one quarter |
| ½ | Ç | ½ | Fraction one half |
| ¾ | ¾ | ¾ | Fraction three-quarters |
| À | À | ¿ | Inverted question mark |
| À | À | À | Capital A, grave accent |
| Á | Á | Á | Capital A, acute accent |
| Â | Â | Â | Capital A, circumflex |
| Ã | Ã | Ã | Capital A, tilde |
| Ä | Ä | Ä | diæresis / umlau |
| Å | Å | Å | Capital A, ring |
| Æ | Æ | Æ | Capital AE, ligature |
| Ç | Ç | Ç | Capital C, cedilla |
| È | È | È | Capital E, grave accent |
| É | É | É | Capital E, acute accent |
| Ê | Ê | Ê | Capital E, circumflex |
| Ë | Ë | Ë | diæresis / umlau |
| Ì | Ì | Ì | Capital I, grave accent |
| Í | Í | Í | Capital I, acute accent |
| Î | Î | Î | Capital I, circumflex |
| Ï | Ï | &Imul; | diæresis / umlau |
| Ð | Ð | Ð | Capital ETH, Icelandic |
| Ñ | Ñ | Ñ | Capital N, tilde |
| Ò | Ò | Ò | Capital O, grave accent |
| Ó | Ó | Ó | Capital O, acute accent |
| Ô | Ô | Ô | Capital O, circumflex |
| Õ | Õ | Õ | Capital O, tilde |
| Ö | Ö | Ö | diæresis / umlau |
| × | × | × | Multiplication sign |
| Ø | Ø | Ø | Capital O, slash |
| Ù | Ù | Ù | Capital U, grave accent |
| Ú | Ú | Ú | Capital U, acute accent |
| Û | Û | Û | Capital U, circumflex |
| Ü | Ü | Ü | diæresis / umlau |
| Ý | Ý | Ý | Capital Y, acute accent |
| Þ | Þ | Þ | Capital Thorn,Icelandic, |
| ß | ß | ß | German sz |
| à | à | à | Small a, grave accent |
| á | á | á | Small a, acute accent |
| â | â | â | Small a, circumflex |
| ã | ã | ã | Small a, tilde |
| ä | ä | ä | diæresis / umlau |
| å | å | å | Small a, ring |
| æ | æ | æ | Small ae ligature |
| ç | ç | ç | Small c, cedilla |
| è | è | è | Small e, grave accent |
| é | é | é | Small e, acute accent |
| ê | ê | ê | Small e, circumflex |
| ë | ë | ë | diæresis / umlau |
| ì | ì | ì | Small i, grave accent |
| í | í | í | Small i, acute accent |
| î | î | î | Small i, circumflex |
| ï | ï | ï | diæresis / umlau |
| ð | ð | ð | Small eth, Icelandic |
| ñ | ñ | ñ | Small n, tilde |
| ò | ò | ò | Small o, grave accent |
| ó | ó | ó | Small o, acute accent |
| ô | ô | ô | Small o, circumflex |
| õ | õ | õ | Small o, tilde |
| ö | ö | ö | diæresis / umlau |
| ÷ | ÷ | ÷ | Division sign, |
| ø | ø | ø | Small o, slash |
| ù | ù | ù | Small u, grave accent |
| ú | ú | ú | Small u, acute accent |
| û | û | û | Small u, circumflex |
| ü | ü | ü | diæresis / umlau |
| ý | ý | ý | Small y, acute accetn |
| þ | þ | þ | Small thorn, Icelandic |
| ÿ | ÿ | ÿ | diæresis / umlaut |
<xmp></xmp>标签使用效果：
