Juqery Learning 3 Selector Sub-Elements and Forms_jquery

:nth-child(index/even/odd/equation)

匹配其父元素下的第N个子或奇偶元素

':eq(index)' 只匹配一个元素，而这个将为每一个父元素匹配子元素。:nth-child从1开始的，而:eq()是从0算起的！

可以使用:
nth-child(even)
:nth-child(odd)
:nth-child(3n)
:nth-child(2)
:nth-child(3n+1)
:nth-child(3n+2)

---

Matches the nth-child of its parent.

While ':eq(index)' matches only a single element, this matches more then one: One for each parent. The specified index is one-indexed, in contrast to :eq() which starst at zero.

返回值

Array

参数

index (Number) : 要匹配元素的序号，从1开始

示例

在每个 ul 查找第 2 个li

HTML 代码:

 
• John

 
• Karl

 
• Brandon

 
• Glen

 
• Tane

 
• Ralph

jQuery 代码:

$("ul li:nth-child(2)")

结果:

[

Karl

,  

Tane

]
--------------------------------------------------------------------------------

:first-child

匹配第一个子元素

':first' 只匹配一个元素，而此选择符将为每个父元素匹配一个子元素

---

Matches the first child of its parent.

While ':first' matches only a single element, this matches more then one: One for each parent.

返回值

Array

示例

在每个 ul 中查找第一个 li

HTML 代码:

 
• John

 
• Karl

 
• Brandon

 
• Glen

 
• Tane

 
• Ralph

jQuery 代码:

$("ul li:first-child")

结果:

[

John

,

Glen

]

--------------------------------------------------------------------------------

:last-child

匹配最后一个子元素

':last'只匹配一个元素，而此选择符将为每个父元素匹配一个子元素

---

Matches the last child of its parent.

While ':last' matches only a single element, this matches more then one: One for each parent.

返回值

Array

示例

在每个 ul 中查找最后一个 li

HTML 代码:

 
• John

 
• Karl

 
• Brandon

 
• Glen

 
• Tane

 
• Ralph

jQuery 代码:

$("ul li:last-child")

结果:

[

Brandon

,

Ralph

]

--------------------------------------------------------------------------------

:only-child

如果某个元素是父元素中唯一的子元素，那将会被匹配

如果父元素中含有其他元素，那将不会被匹配。

---

Matches the only child of its parent.

If the parent has other child elements, nothing is matched.

返回值

Array

示例

在 ul 中查找是唯一子元素的 li

HTML 代码:

 
• John

 
• Karl

 
• Brandon

 
• Glen

jQuery 代码:

$("ul li:only-child")

结果:

[

Glen

]

--------------------------------------------------------------------------------

:input

匹配所有 input, textarea, select 和 button 元素

---

Matches all input, textarea, select and button elements.

返回值

Array

示例

查找所有的input元素

HTML 代码:

 
 
 
 
 
 
 
 
 
 
 
 

jQuery 代码:

$(":input")

结果:

[ , , , , , , , , ]

--------------------------------------------------------------------------------

:text

匹配所有的单行文本框

---

Matches all input elements of type text.

返回值

Array

示例

查找所有文本框

HTML 代码:

 
 
 
 
 
 
 
 
 
 
 
 

jQuery 代码:

$(":text")

结果:

[ ]

--------------------------------------------------------------------------------

:password

匹配所有密码框

---

Matches all input elements of type password.

返回值

Array

示例

查找所有密码框

HTML 代码:

 
 
 
 
 
 
 
 
 
 
 
 

jQuery code:

$(":password")

Result:

[ ]

-------------------------- -------------------------------------------------- --

:radio

Match all radio buttons

---

Matches all input elements of type radio.

Return value

Array

Example

Find all radio buttons

HTML code:

jQuery code:

$(":radio")

Result:

[

]

-------------------------- -------------------------------------------------- --

:submit

Match all submit buttons

---

Matches all input elements of type submit.

Return value

Array

Example

Find all submit buttons

HTML code:

jQuery code:

$(":submit")

Result:

[

]

The others are the same: image ,:reset,:button,:file,:hidden !@# @!%$%