The HTML <ul> 元素 ( 或 HTML 无序列表元素) 代表多项的无序列表,即无数值排序项的集合,且它们在列表中的顺序是没有意义的。通常情况下,无序列表项的头部可以是几种形式,如一个点,一个圆形或方形。头部的风格并不是在页面的HTML描述定义, 但在其相关的CSS 可以用 list-style-type 属性。
There is no limitation to the depth and imbrication of lists defined with the <ol> and <ul> elements.
Usage note: The
<ol> and <ul> elements both represent a list of items. They differ in that, with the <ol> element, the order is meaningful. As a rule of thumb to determine which one to use, try changing the order of the list items; if the meaning is changed, the <ol> element should be used, otherwise you can use <ul>.Usage context
| Content categories | Flow content |
| Permitted content | zero or more <li> elements, eventually mixed with <ol> and <ul> elements. |
| Tag omission | none, both the start tag and the end tag are mandatory |
| Permitted parent elements | any element that accept flowing content |
| DOM Interface | HTMLUListElement |
Attributes
This element includes the global attributes.
compact- This Boolean attribute hints that the list should be rendered in a compact style. The interpretation of this attribute depends on the user agent and it doesn't work in all browsers.
Usage note: Do not use this attribute, as it has been deprecated: the
<ul>element should be styled using CSS. To give a similar effect as the compact attribute, the CSS property line-height can be used with a value of 80%.
type- Used to set the bullet style for the list. The values defined under HTML3.2 and the transitional version of HTML 4.0/4.01 are:
circle,disc,- and
square.
A fourth bullet type has been defined in the WebTV interface, but not all browsers support it:
triangle.If not present and if no CSS
list-style-typeproperty does apply to the element, the user agent decide to use a kind of bullets depending on the nesting level of the list.Usage note: Do not use this attribute, as it has been deprecated; use the CSSlist-style-typeproperty instead.
Examples
Simple example
<ul> <li>first item</li> <li>second item</li> <li>third item</li> </ul>
Above HTML will output:
- first item
- second item
- third item
Nesting list
<ul> <li>first item</li> <li>second item <!-- Look, the closing </li> tag is not placed here! --> <ul> <li>second item first subitem</li> <li>second item second subitem <!-- Same for the second nested unordered list! --> <ul> <li>second item second subitem first sub-subitem</li> <li>second item second subitem second sub-subitem</li> <li>second item second subitem third sub-subitem</li> </ul> </li> <!-- Closing </li> tag for the li that contains the third unordered list --> <li>second item third subitem</li> </ul> </li> <!-- Here is the closing </li> tag --> <li>third item</li> </ul>
Above HTML will output:
- first item
- second item
- second item first subitem
- second item second subitem
- second item second subitem first sub-subitem
- second item second subitem second sub-subitem
- second item second subitem third sub-subitem
- second item third subitem
- third item
Nested <ul> and <ol>
<ul>
<li>first item</li>
<li>second item <!-- Look, the closing </li> tag is not placed here! -->
<ol>
<li>second item first subitem</li>
<li>second item second subitem</li>
<li>second item third subitem</li>
</ol>
</li> <!-- Here is the closing </li> tag -->
<li>third item</li>
</ul>
Above HTML will output:
- first item
- second item
- second item first subitem
- second item second subitem
- second item third subitem
- third item
See also
- Other list-related HTML Elements:
<ol>,<li>,<menu>and the obsolete<dir>; - CSS properties that may be specially useful to style the <ul> element:
- the list-style property, useful to choose the way the ordinal is displayed,
- CSS counters, useful to handle complex nested lists,
- the line-height property, useful to simulate the deprecated
compactattribute, - the margin property, useful to control the indent of the list.