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HomeWeb Front-endJS TutorialSummary of jQuer selector wildcard and selector instance usage

The

wildcard character in jquery selector is often used. The wildcard character is very easy to use when controlling the input tag . The general usage is summarized as follows:

1. Selector

(1) Wildcard:

$("input[id^='code']");//id属性以code开始的所有input标签
$("input[id$='code']");//id属性以code结束的所有input标签
$("input[id*='code']");//id属性包含code的所有input标签
$("input[name^='code']");//name属性以code开始的所有input标签
$("input[name$='code']");//name属性以code结束的所有input标签
$("input[name*='code']");//name属性包含code的所有input标签
$("input[name*='code']").each(fuction(){
  var sum=0;
if($(this).val()!=""){
 sum=parseInt(sum)+parseInt($(this).val());
}
$("#").text(sum);
})

(2) Based on indexSelect

$("tbody tr:even"); //Select all tr ​​tags with an even number
$("tbody tr:odd"); //Select an odd number with an index All tr ​​tags

(3) Get the number of inputs of the next-level node of jqueryObj

jqueryObj.children("input").length;

(4) Get the child of the tag with class main All tags under the node

$(".main > a");

(5) Select the tag immediately adjacent to

jqueryObj.next("p");//获取jqueryObj标签的后面紧邻的一个p,nextAll获取所有

2. Filter

//not
$("#code input:not([id^='code'])");//id为code标签内不包含id以code开始的所有input标签

3. Event

//处理文本框上的键盘操作
jqueryObj.keyup(function(event){
var keyCode = event.which;//获取当前按下键盘的键值,回车键为13
}

4. Tool function

$('#someField').val($.trim($('#someField').val()));//消除空格,语法:$.trim(value)

ps: jQuery selector summary

jQuery’s selector is extremely powerful. Here is a brief summary of commonly used element search methods

$("#myELement") Select the element whose id value is equal to myElement. The id value cannot be repeated. There can only be one id value myElement in the document, so what you get is the only element

$ ("p") Select all p tag elements and return the p elementarray

$(".myClass") Select all elements using the css of the myClass class

$("*") To select all elements in the document, you can use a variety of selection methods for joint selection: For example, $("#myELement,p,.myclass")

Cascading selector:

##$("form input") Select all input elements in the form element

$("#main > *" ) Select all the sub -elements of the ID value to Main
$ ("Label + Input") Select the next Input element node of all Label elements. All input tag elements
$("#prev ~ p") Sibling selector, this selector returns all p tags belonging to the same parent element of the tag element with id prev

Basic filter selector:

$("tr:first") Select the first one of all tr ​​elements

$("tr:last") Select The last
$("input:not(:checked) + span") of all tr ​​elements

Filter out: all input elements of the checked selector


$ ("TR: EVEN") Select 0, 2, 4 ... ... Performance of all TR elements (Note: Because the number of elements selected is an array, so the serial number is from 0 from 0 Start)

$("tr:odd") Select the 1st, 3rd, 5th... elements of all tr ​​elements
$("td:eq(2)") Select all The td element with the sequence number 2 in the td element
$("td:gt(4)")                                                                                                            -                                                                           All td elements with sequence numbers less than 4 in the td element
$(":header")
$("p:animated")

Content filter selector:
$("p:contains('John')") Select all elements containing John text in p

$("td:empty") Select all An array of empty td elements (not including text nodes)

$("p:has(p)") Select all p elements containing p tags
$("td:parent") Select all Element array with td as parent node

Visual filter selector:

$("p:hidden")        选择所有的被hidden的p元素
$("p:visible")        选择所有的可视化的p元素

属性过滤选择器:

$("p[id]")           选择所有含有id属性的p元素
$("input[name='newsletter']")    选择所有的name属性等于'newsletter'的input元素
$("input[name!='newsletter']") 选择所有的name属性不等于'newsletter'的input元素
$("input[name^='news']")         选择所有的name属性以'news'开头的input元素
$("input[name$='news']")         选择所有的name属性以'news'结尾的input元素
$("input[name*='man']")          选择所有的name属性包含'news'的input元素
$("input[id][name$='man']")    可以使用多个属性进行联合选择,该选择器是得到所有的含有id属性并且那么属性以man结尾的元素

子元素过滤选择器:

$("ul li:nth-child(2)"),$("ul li:nth-child(odd)"),$("ul li:nth-child(3n + 1)") 
  $("p span:first-child")          返回所有的p元素的第一个子节点的数组
$("p span:last-child")           返回所有的p元素的最后一个节点的数组
$("p button:only-child")       返回所有的p中只有唯一一个子节点的所有子节点的数组

表单元素选择器: 

$(":input")                  选择所有的表单输入元素,包括input, textarea, select 和 button 

$(":text")                     选择所有的text input元素
$(":password")           选择所有的password input元素
$(":radio")                   选择所有的radio input元素
$(":checkbox")            选择所有的checkbox input元素
$(":submit")               选择所有的submit input元素
$(":image")                 选择所有的image input元素
$(":reset")                   选择所有的reset input元素
$(":button")                选择所有的button input元素
$(":file")                     选择所有的file input元素
$(":hidden")               选择所有类型为hidden的input元素或表单的隐藏域

表单元素过滤选择器: 

$(":enabled")             选择所有的可操作的表单元素
$(":disabled")            选择所有的不可操作的表单元素
$(":checked")            选择所有的被checked的表单元素
$("select option:selected") 选择所有的select 的子元素中被selected的元素

选取一个 name 为”S_03_22″的input text框的上一个td的text值

$(”input[@ name =S_03_22]“).parent().prev().text()

名字以”S_”开始,并且不是以”_R”结尾的

$(”input[@ name ^='S_']“).not(”[@ name $='_R']“)

一个名为 radio_01的radio所选的值

$(”input[@ name =radio_01][@checked]“).val();

$("A B") 查找A元素下面的所有子节点,包括非直接子节点
$("A>B") 查找A元素下面的直接子节点
$("A+B") 查找A元素后面的兄弟节点,包括非直接子节点
$("A~B") 查找A元素后面的兄弟节点,不包括非直接子节点

1. $("A B") 查找A元素下面的所有子节点,包括非直接子节点

例子:找到表单中所有的 input 元素

HTML 代码: 

<form>
<label>Name:</label>
<input name="name" />
<fieldset>
   <label>Newsletter:</label>
   <input name="newsletter" />
</fieldset>
</form>
<input name="none" />

jQuery 代码:

$("form input")

结果:

[ <input name="name" />, <input name="newsletter" /> ]

2. $("A>B") 查找A元素下面的直接子节点

例子:匹配表单中所有的子级input元素。

HTML 代码: 

<form>
<label>Name:</label>
<input name="name" />
<fieldset>
   <label>Newsletter:</label>
   <input name="newsletter" />
</fieldset>
</form>
<input name="none" />

jQuery 代码:

$("form > input")

结果:

[ <input name="name" /> ]

3. $("A+B") 查找A元素后面的兄弟节点,包括非直接子节点

例子:匹配所有跟在 label 后面的 input 元素

HTML 代码: 

<form>
<label>Name:</label>
<input name="name" />
<fieldset>
   <label>Newsletter:</label>
   <input name="newsletter" />
</fieldset>
</form>
<input name="none" />

jQuery 代码:

$("label + input")

结果:

[ <input name="name" />, <input name="newsletter" /> ]

4. $("A~B") 查找A元素后面的兄弟节点,不包括非直接子节点

例子:找到所有与表单同辈的 input 元素

HTML 代码:

<form>
<label>Name:</label>
<input name="name" />
<fieldset>
   <label>Newsletter:</label>
   <input name="newsletter" />
</fieldset>
</form>
<input name="none" />

jQuery 代码: 

$("form ~ input")

结果:

[ <input name="none" /> ]

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