如下代码，在“你好”之间手动敲了很多个空格，会怎么展示？
<p>你 好</p>
实际只会显示为1个空格，html而忽略多余的空格，
那如果想要在“你好”之间加入多个空格，怎么办？
此时就需要用到html特殊字符了，在html中 会被解析为空格。
<p>你 好</p>
html特殊字符对照表
| 特殊符号 | 命名实体 | 十进制编码 | 特殊符号 | 命名实体 | 十进制编码 | 特殊符号 | 命名实体 | 十进制编码 |
| Α | Α | Α | Β | Β | Β | Γ | Γ | Γ |
| Δ | Δ | Δ | Ε | Ε | Ε | Ζ | Ζ | Ζ |
| Η | Η | Η | Θ | Θ | Θ | Ι | Ι | Ι |
| Κ | Κ | Κ | Λ | Λ | Λ | Μ | Μ | Μ |
| Ν | Ν | Ν | Ξ | Ξ | Ξ | Ο | Ο | Ο |
| Π | Π | Π | Ρ | Ρ | Ρ | Σ | Σ | Σ |
| Τ | Τ | Τ | Υ | Υ | Υ | Φ | Φ | Φ |
| Χ | Χ | Χ | Ψ | Ψ | Ψ | Ω | Ω | Ω |
| α | α | α | β | β | β | γ | γ | γ |
| δ | δ | δ | ε | ε | ε | ζ | ζ | ζ |
| η | η | η | θ | θ | θ | ι | ι | ι |
| κ | κ | κ | λ | λ | λ | μ | μ | μ |
| ν | ν | ν | ξ | ξ | ξ | ο | ο | ο |
| π | π | π | ρ | ρ | ρ | ς | ς | ς |
| σ | σ | σ | τ | τ | τ | υ | υ | υ |
| φ | φ | φ | χ | χ | χ | ψ | ψ | ψ |
| ω | ω | ω | ϑ | ϑ | ϑ | ϒ | ϒ | ϒ |
| ϖ | ϖ | ϖ | • | • | • | … | … | … |
| ′ | ′ | ′ | ″ | ″ | ″ | ‾ | ‾ | ‾ |
| ⁄ | ⁄ | ⁄ | ℘ | ℘ | ℘ | ℑ | ℑ | ℑ |
| ℜ | ℜ | ℜ | ™ | ™ | ™ | ℵ | ℵ | ℵ |
| ← | ← | ← | ↑ | ↑ | ↑ | → | → | → |
| ↓ | ↓ | ↓ | ↔ | ↔ | ↔ | ↵ | ↵ | ↵ |
| ⇐ | ⇐ | ⇐ | ⇑ | ⇑ | ⇑ | ⇒ | ⇒ | ⇒ |
| ⇓ | ⇓ | ⇓ | ⇔ | ⇔ | ⇔ | ∀ | ∀ | ∀ |
| ∂ | ∂ | ∂ | ∃ | ∃ | ∃ | ∅ | ∅ | ∅ |
| ∇ | ∇ | ∇ | ∈ | ∈ | ∈ | ∉ | ∉ | ∉ |
| ∋ | ∋ | ∋ | ∏ | ∏ | ∏ | ∑ | ∑ | − |
| − | − | − | ∗ | ∗ | ∗ | √ | √ | √ |
| ∝ | ∝ | ∝ | ∞ | ∞ | ∞ | ∠ | ∠ | ∠ |
| ∧ | ∧ | ⊥ | ∨ | ∨ | ⊦ | ∩ | ∩ | ∩ |
| ∪ | ∪ | ∪ | ∫ | ∫ | ∫ | ∴ | ∴ | ∴ |
| ∼ | ∼ | ∼ | ≅ | ≅ | ≅ | ≈ | ≈ | ≅ |
| ≠ | ≠ | ≠ | ≡ | ≡ | ≡ | ≤ | ≤ | ≤ |
| ≥ | ≥ | ≥ | ⊂ | ⊂ | ⊂ | ⊃ | ⊃ | ⊃ |
| ⊄ | ⊄ | ⊄ | ⊆ | ⊆ | ⊆ | ⊇ | ⊇ | ⊇ |
| ⊕ | ⊕ | ⊕ | ⊗ | ⊗ | ⊗ | ⊥ | ⊥ | ⊥ |
| ⋅ | ⋅ | ⋅ | ⌈ | ⌈ | ⌈ | ⌉ | ⌉ | ⌉ |
| ⌊ | ⌊ | ⌊ | ⌋ | ⌋ | ⌋ | ◊ | ◊ | ◊ |
| ♠ | ♠ | ♠ | ♣ | ♣ | ♣ | ♥ | ♥ | ♥ |
| ♦ | ♦ | ♦ | |   | ¡ | ¡ | ¡ | |
| ¢ | ¢ | ¢ | £ | £ | £ | ¤ | ¤ | ¤ |
| ¥ | ¥ | ¥ | ¦ | ¦ | ¦ | § | § | § |
| ¨ | ¨ | ¨ | © | © | © | ª | ª | ª |
| « | « | « | ¬ | ¬ | ¬ | ­ | ­ | |
| ® | ® | ® | ¯ | ¯ | ¯ | ° | ° | ° |
| ± | ± | ± | ² | ² | ² | ³ | ³ | ³ |
| ´ | ´ | ´ | µ | µ | µ | " | " | " |
| < | < | < | > | > | > | ' | ' |
