HTML5常见的取值与单位
长度单位包括
相对长度单位包括：em, ex, ch, rem, vw, vh, vmax, vmin
绝对长度单位包括：cm, mm, q, in, pt, pc, px
ch:数字“0”的宽度
em:相对于当前对象内文本的字体尺寸。如当前对行内文本的字体尺寸未被人为设置，则相对于浏览器的默认字体尺寸。
ex:相对长度单位。相对于字符“x”的高度。通常为字体高度的一半。如当前对行内文本的字体尺寸未被人为设置，则相对于浏览器的默认字体尺寸。
rem:相对于根元素(即html元素)font-size计算值的倍数
vw:相对于视口的宽度。视口被均分为100单位的vw
vh:相对于视口的高度。视口被均分为100单位的vh
vmax:相对于视口的宽度或高度中较大的那个。其中最大的那个被均分为100单位的vmax
vmin:相对于视口的宽度或高度中较大的那个。其中最大的那个被均分为100单位的vmax
cm:厘米 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
mm:毫米 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
q:1/4毫米 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
in:英寸 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
pt:点 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
pc:派卡 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
px:像素 1in = 2.54cm = 25.4 mm = 101.6q = 72pt = 6pc = 96px
| Pixels | EMs | Percent | Points |
|---|---|---|---|
| 6px | 0.375em | 37.5% | 5pt |
| 7px | 0.438em | 43.8% | 5pt |
| 8px | 0.5em | 50% | 6pt |
| 9px | 0.563em | 56.3% | 7pt |
| 10px | 0.625em | 62.5% | 8pt |
| 11px | 0.688em | 68.8% | 8pt |
| 12px | 0.75em | 75% | 9pt |
| 13px | 0.813em | 81.3% | 10pt |
| 14px | 0.875em | 87.5% | 11pt |
| 15px | 0.938em | 93.8% | 11pt |
| 16px | 1em | 100% | 12pt |
| 17px | 1.063em | 106.3% | 13pt |
| 18px | 1.125em | 112.5% | 14pt |
| 19px | 1.188em | 118.8% | 14pt |
| 20px | 1.25em | 125% | 15pt |
| 21px | 1.313em | 131.3% | 16pt |
| 22px | 1.375em | 137.5% | 17pt |
| 23px | 1.438em | 143.8% | 17pt |
| 24px | 1.5em | 150% | 18pt |