JQuery Package Set Selector

1.Dom objects and jquery package set conversions

In traditional JavaScript development, we all get DOM objects first, such as:

var div = document.getElementById ("Testdiv");
var divs = document.getelementsbytagname ("div");

We often use the document.getElementById method to get a single Dom object based on the ID, or use the document.getElementsByTagName method to get a collection of Dom objects based on the HTML tag name.

Alternatively, in the event function, you can use the this reference event in the method function to trigger the object, or use the event object's target (FF) or srcelement (iIE6) to get to the DOM object that raised the event.

If you want to use the functions provided by jquery, first convert the DOM object into a jquery wrapper set.

jquery can get the package set directly, such as $ ("#testDiv");

You can also convert an already acquired DOM object into a jquery package set,

var domobject = document.getElementById ("Testdiv");

var jqueryobject = $ (domobject);

The jquery wrapper set is a collection, so we can access one of the elements through the indexer:

var domobject = $ ("#testDiv") [0];

Note that the index returned by the indexer is no longer a jquery wrapper set, but a DOM object!
Some of the traversal methods of the jquery package set, such as each (), can pass the traversal function, and this in the traversal function is also a DOM element, such as:

$ ("#testDiv"). each (function () {alert (this)})

What if we want to manipulate the DOM object using jquery's method? You can use the conversion method described above:

$ ("#testDiv"). each (function () {$ (this). HTML ("Modify content")})

2.jQuery Selector

In DOM programming we can only use finite functions to get DOM objects by ID or tagname.

In jquery, which is quite different, jquery provides an exceptionally powerful selector to help us get the objects on the page and return the objects as a jquery wrapper set.

1. Base Selector Basics

Name	Description	Example
#id	Select based on element ID	$ ("divID") select element with ID divid
Element	Depending on the name of the element, select	$ ("a") Select all <a> elements
. class	Based on the CSS class selection of the element	$ (". bgred") Select the element for which the CSS class is bgred
*	Select all elements	$ ("*") Select all elements of the page
Selector1, Selector2, Selectorn	You can separate several selectors with "," and then spell a selector string. The contents of these selectors will be selected at the same time.	$ ("#divId, A,. bgred")

2. Hierarchy Selector Hierarchy

Name	Description	Example
Ancestor descendant	Use form input to select all input elements in the form. That is, ancestor (ancestor) is from, descendant (descendants) is input.	$ (". Bgred div") selects all <div> elements in the CSS class for bgred elements.
Parent > Child	Select the direct child node of parent. Child must be contained in parent and the parent class is the parents element.	$ (". Mylist>li") Select the CSS class as a direct child node <li> object in the MyList element.
Prev + Next	Prev and Next are two elements of the same level. Select the next element after the Prev element.	$ ("#hibiscus +img") is selected in the IMG object after the ID of the hibiscus element.
Prev ~ siblings	Select the element that is filtered according to siblings after Prev Note: Siblings is a filter	$ ("#someDiv ~[title]") Select all elements with the title attribute after the object with ID somediv

3. Basic Filter Basic Filters

Name	Description	Example
: First	Match the first element found	Find the first row of a table: $ ("Tr:first")
: Last	Match the last element found	Find the last line of the table: $ ("Tr:last")
: Not (selector)	Removes all elements that match a given selector	Find all the unselected input elements: $ ("Input:not (: Checked)")
: Even	Matches all elements with an even number of index values, counting from 0	Find table 1, 3, 5 ... line: $ ("Tr:even")
: Odd	Matches all elements with an odd index value, counting from 0	Find 2, 4, and 6 rows of a table: $ ("tr:odd")
: EQ (Index)	An element that matches a given index value Note: Index is counted starting from 0	Find second line: $ ("Tr:eq (1)")
: GT (Index)	Match all elements greater than the given index value Note: Index is counted starting from 0	Find the second third row, where the index value is 1 and 2, or greater than 0: $ ("tr:gt (0)")
: LT (Index)	Select elements with index less than N in the result set Note: Index is counted starting from 0	Find the first second row, that is, the index value is 0 and 1, which is smaller than 2: $ ("Tr:lt (2)")
: Header	Select All header tags of the h1,h2,h3 category.	Add background color to all headings in the page: $ (": Header"). CSS ("Background", "#EEE");
: Animated	Matches all elements that are performing an animation effect	An animated effect is only performed on elements that do not animate: $ ("#run"). Click (function () { $ ("Div:not (: Animated)"). Animate ({left: "+=20"}, 1000); });

4. Content Filter Contents Filters

Name	Description	Example
: Contains (text)	Matches the element containing the given text	Find all DIV elements that contain "John": $ ("Div:contains (' John ')")
: Empty	Matches all empty elements that do not contain child elements or text	Find all empty elements that do not contain child elements or text: $ ("Td:empty")
: Has (selector)	Matches the element that contains the element that the selector matches	Add a text class to all DIV elements that contain the P element: $ ("Div:has (P)"). AddClass ("test");
:p arent	Match elements that contain child elements or text	Find all TD elements that contain child elements or text: $ ("td:parent")

5. Visibility Filter Visibility Filters

Name	Description	Example
: Hidden	Match all the Invisible elements Note: In the 1.3.2 release, hidden matches an element that itself or the parent does not occupy space in the document. If you use the CSS visibility property so that it does not display but occupies a placeholder, you do not enter hidden.	Find all the Invisible TR elements: $ ("Tr:hidden")
: Visible	Match all visible elements	Find all the Visible TR elements: $ ("tr:visible")

6. Attribute Filter Attribute Filters

Name	Description	Example
[Attribute]	Match the element containing the given property	Find all DIV elements that contain ID attributes: $ ("Div[id]")
[Attribute=value]	Matches a given property as an element of a particular value	Find all the name attribute is the INPUT element of newsletter: $ ("input[name= ' newsletter ')"). attr ("Checked", true);
[Attribute!=value]	Matches a given property is an element that does not contain a particular value	Find all the name attributes that are not newsletter input elements: $ ("input[name!= ' newsletter ')"). attr ("Checked", true);
[Attribute^=value]	Matches a given property is an element that starts with some value	$ ("input[name^= ' News ']")
[Attribute$=value]	Matches a given property is an element that ends with some value	Find all input elements with the name ' letter ': $ ("input[name$= ' letter ']")
[Attribute*=value]	Matches a given property to an element that contains some value	Find all the input elements that name contains ' man ': $ ("input[name*= ' Man ']")
[AttributeFilter1] [AttributeFilter2] [Attributefiltern]	A composite property selector that needs to be used when multiple conditions are met.	Find all the ID attributes, and its name attribute is the end of the man: $ ("input[id][name$= ' Man ']")

7. Sub-element filter child Filters

Name	Description	Example
: Nth-child (Index/even/odd/equation)	Matches the nth child or odd and even element under its parent element ': EQ (index) matches only one element, and this will match child elements for each parent element. : Nth-child starting from 1, and: Eq () is from 0! You can use: Nth-child (even) : Nth-child (Odd) : Nth-child (3n) : Nth-child (2) : Nth-child (3n+1) : Nth-child (3n+2)	Find the 2nd Li in each UL: $ ("UL Li:nth-child (2)")
: First-child	Match first child element ': First ' matches only one element, and this selector will match one child element for each parent element	Find the first Li in each UL: $ ("ul Li:first-child")
: Last-child	Match last child element ': Last ' matches only one element, and this selector will match one child element for each parent element	Find the last Li in each ul: $ ("ul Li:last-child")
: Only-child	If an element is the only child element in the parent element, it will be matched If the parent element contains other elements, it will not be matched.	Find the LI in ul that is the only child element: $ ("ul Li:only-child")

8. Form selector Forms

Name	Description	Explain
: input	Matches all input, textarea, select, and button elements	To find all input elements: $ (": input")
: Text	Match all the text boxes	Find all text boxes: $ (": Text")
:p Assword	Match all Password boxes	Find all Password boxes: $ (":p Assword")
: Radio	Match all radio buttons	Find all radio buttons
: checkbox	Match all check boxes	Find all check boxes: $ (": checkbox")
: Submit	Match all Submit buttons	Find all Submit buttons: $ (": Submit")
: Image	Match all image fields	Match all image fields: $ (": Image")
: RESET	Match all reset buttons	Find all reset buttons: $ (": Reset")
: button	Match all buttons	Find all buttons: $ (": Button")
: File	Match all file domains	Find all file domains: $ (": File")

9. Form Filter Form Filters

Name	Description	Explain
: Enabled	Match all available elements	To find all available input elements: $ ("input:enabled")
:d isabled	Match all unavailable elements	To find all input elements that are not available: $ ("input:disabled")
: Checked	Matches all selected selected elements (Checkboxes, radio boxes, etc., excluding option in select)	Find all selected check box elements: $ ("input:checked")
: Selected	Match all of the selected option elements	To find all selected option elements: $ ("Select Option:selected")