原网址如下：
[url] http://www.php100.com/html/program/html/2013/0903/1052.htm[/url]
有些字符在HTML里有特别的含义，比如小于号<就表示HTML Tag的开始，这个小于号是不显示在我们最终看到的网页里的。那如果我们希望在网页中显示一个小于号，该怎么办呢？
这就要说到HTML字符实体(HTML Character Entities)了。
一个字符实体(Character Entity)分成三部分：第一部分是一个&符号，英文叫ampersand；第二部分是实体(Entity)名字或者是#加上实体(Entity)编号；第三部分是一个分号。
比如，要显示小于号，就可以写<或者<。
用实体(Entity)名字的好处是比较好理解，一看lt，大概就猜出是less than的意思，但是其劣势在于并不是所有的浏览器都支持最新的Entity名字。而实体(Entity)编号，各种浏览器都能处理。
注意：Entity是区分大小写的。
如何显示空格
通常情况下，HTML会自动截去多余的空格。不管你加多少空格，都被看做一个空格。比如你在两个字之间加了10个空格，HTML会截去9个空格，只保留一个。为了在网页中增加空格，你可以使用 表示空格。
最常用的字符实体(Character Entities)
| 显示结果 说明 Entity Name Entity Number |
| 显示一个空格 |
| < 小于 < < |
| > 大于 > > |
| & &符号 & & |
| " 双引号 " " |
其他常用的字符实体(Character Entities)
| 显示结果 说明 Entity Name Entity Number |
| © 版权 © © |
| ® 注册商标 ® ® |
| × 乘号 × × |
| ÷ 除号 ÷ ÷ |
更多字符实体(Character Entities)
| 字符 十进制字符编号 实体名字 说明 | |
| --- � --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 制表符Horizontal tab | |
| --- --- 换行Line feed | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 回车Carriage Return | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- --- 未使用Unused | |
| --- Space | |
| ! ! --- 惊叹号Exclamation mark | |
| " " " 双引号Quotation mark | |
| # # --- 数字标志Number sign | |
| $ $ --- 美元标志Dollar sign | |
| % % --- 百分号Percent sign | |
| & & & Ampersand | |
| ' ' --- 单引号Apostrophe | |
| ( ( --- 小括号左边部分Left parenthesis | |
| ) ) --- 小括号右边部分Right parenthesis | |
| * * --- 星号Asterisk | |
| + + --- 加号Plus sign | |
| , , --- 逗号Comma | |
| - - --- 连字号Hyphen | |
| . . --- 句号Period (fullstop) | |
| / / --- 斜杠Solidus (slash) | |
| 0 0 --- 数字0 Digit 0 | |
| 1 1 --- 数字1 Digit 1 | |
| 2 2 --- 数字2 Digit 2 | |
| 3 3 --- 数字3 Digit 3 | |
| 4 4 --- 数字4 Digit 4 | |
| 5 5 --- 数字5 Digit 5 | |
| 6 6 --- 数字6 Digit 6 | |
| 7 7 --- 数字7 Digit 7 | |
| 8 8 --- 数字8 Digit 8 | |
| 9 9 --- 数字9 Digit 9 | |
| : : --- 冒号Colon | |
| ; ; --- 分号Semicolon | |
| < < < 小于号Less than | |
| = = --- 等于符号Equals sign | |
| > > > 大于号Greater than | |
| ? ? --- 问号Question mark | |
| @ @ --- Commercial at | |
| A A --- 大写A Capital A | |
| B B --- 大写B Capital B | |
| C C --- 大写C Capital C | |
| D D --- 大写D Capital D | |
| E E --- 大写E Capital E | |
| F F --- 大写F Capital F | |
| G G --- 大写G Capital G | |
| H H --- 大写H Capital H | |
| I I --- 大写J Capital I | |
| J J --- 大写K Capital J | |
| K K --- 大写L Capital K | |
| L L --- 大写K Capital L | |
| M M --- 大写M Capital M | |
| N N --- 大写N Capital N | |
| O O --- 大写O Capital O | |
| P P --- 大写P Capital P | |
| Q Q --- 大写Q Capital Q | |
| R R --- 大写R Capital R | |
| S S --- 大写S Capital S | |
| T T --- 大写T Capital T | |
| U U --- 大写U Capital U | |
| V V --- 大写V Capital V | |
| W W --- 大写W Capital W | |
| X X --- 大写X Capital X | |
| Y Y --- 大写Y Capital Y | |
| Z Z --- 大写Z Capital Z | |
| [ [ --- 中括号左边部分Left square bracket | |
| \ \ --- 反斜杠Reverse solidus (backslash) | |
| ] ] --- 中括号右边部分Right square bracket | |
| ^ ^ --- Caret | |
| _ _ --- 下划线Horizontal bar (underscore) | |
| ` ` --- 尖重音符Acute accent | |
| a a --- 小写a Small a | |
| b b --- 小写b Small b | |
| c c --- 小写c Small c | |
| d d --- 小写d Small d | |
| e e --- 小写e Small e | |
| f f --- 小写f Small f | |
| g g --- 小写g Small g | |
| h h --- 小写h Small h | |
| i i --- 小写i Small i | |
| j j --- 小写j Small j | |
| k k --- 小写k Small k | |
| l l --- 小写l Small l | |
| m m --- 小写m Small m | |
| n n --- 小写n Small n | |
| o o --- 小写o Small o | |
| p p --- 小写p Small p | |
| q q --- 小写q Small q | |
| r r --- 小写r Small r | |
| s s --- 小写s Small s | |
| t t --- 小写t Small t | |
| u u --- 小写u Small u | |
| v v --- 小写v Small v | |
| w w --- 小写w Small w | |
| x x --- 小写x Small x | |
| y y --- 小写y Small y | |
| z z --- 小写z Small z | |
| { { --- 大括号左边部分Left curly brace | |
| | --- 竖线Vertical bar | |
| } } --- 大括号右边部分Right curly brace | |
| ~ ~ --- Tilde | |
| --- --- 未使用Unused | |
| 空格Nonbreaking space | |
| ¡ ¡ ¡ Inverted exclamation | |
| ¢ ¢ ¢ 货币分标志Cent sign | |
| £ £ £ 英镑标志Pound sterling | |
| ¤ ¤ ¤ 通用货币标志General currency sign | |
| ¥ ¥ ¥ 日元标志Yen sign | |
| ¦ ¦ ¦ or &brkbar; 断竖线Broken vertical bar | |
| § § § 分节号Section sign | |
| ¨ ¨ ¨ or ¨ 变音符号Umlaut | |
| © © © 版权标志Copyright | |
| ª ª ª Feminine ordinal | |
| « « « Left angle quote, guillemet left | |
| ¬ ¬ ¬ Not sign | |
| Soft hyphen | |
| ® ® ® 注册商标标志Registered trademark | |
| ¯ ¯ ¯ or &hibar; 长音符号Macron accent | |
| ° ° ° 度数标志Degree sign | |
| ± ± ± 加或减Plus or minus | |
| ² ² ² 上标2 Superscript two | |
| ³ ³ ³ 上标3 Superscript three | |
| ´ ´ ´ 尖重音符Acute accent | |
| µ µ µ Micro sign | |
| ¶ ¶ ¶ Paragraph sign | |
| · · · Middle dot | |
| ¸ ¸ ¸ Cedilla | |
| ¹ ¹ ¹ 上标1 Superscript one | |
| º º º Masculine ordinal | |
| » » » Right angle quote, guillemet right | |
| ¼ ¼ ¼ 四分之一Fraction one-fourth | |
| ½ ½ ½ 二分之一Fraction one-half | |
| ¾ ¾ ¾ 四分之三Fraction three-fourths | |
| ¿ ¿ ¿ 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 Capital A, di?esis / umlaut | |
| 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 Capital E, di?esis / umlaut | |
| Ì Ì Ì Capital I, grave accent | |
| Í Í Í Capital I, acute accent | |
| Î Î Î Capital I, circumflex | |
| Ï Ï Ï Capital I, di?esis / umlaut | |
| 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 Capital O, di?esis / umlaut | |
| × × × 乘号Multiply 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 Capital U, di?esis / umlaut | |
| Ý Ý Ý Capital Y, acute accent | |
| Þ Þ Þ Capital Thorn, Icelandic | |
| ß ß ß Small sharp s, 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 Small a, di?esis / umlaut | |
| 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 Small e, di?esis / umlaut | |
| ì ì ì Small i, grave accent | |
| í í í Small i, acute accent | |
| î î î Small i, circumflex | |
| ï ï ï Small i, di?esis / umlaut | |
| 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 Small o, di?esis / umlaut | |
| ÷ ÷ ÷ 除号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 Small u, di?esis / umlaut | |
| ý ý ý Small y, acute accent | |
| þ þ þ Small thorn, Icelandic | |
| ÿ ÿ ÿ Small y, umlaut |