选择某个网页元素，然后进行对其进行某种操作
- HTML/DOM manipulation
- CSS manipulation
- HTML event methods
- Effects and animations
- AJAX
- Utilities
With jQuery you select (query) HTML elements and perform "actions" on them.
$(selector).action()
$(document).ready(function(){
// jquery methods go here
});
$(function(){
// jquery methods go here
});
jQuery Selectors
| * | $("*") | All elements |
| #id | $("#lastname") | The element with id="lastname" |
| .class | $(".intro") | All elements with class="intro" |
| .class,.class | $(".intro,.demo") | All elements with the class "intro" or "demo" |
| element | $("p") | All <p> elements |
| el1,el2,el3 | $("h1,div,p") | All <h1>, <div> and <p> elements |
| :first | $("p:first") | The first <p> element |
| :last | $("p:last") | The last <p> element |
| :even | $("tr:even") | All even <tr> elements |
| :odd | $("tr:odd") | All odd <tr> elements |
| :first-child | $("p:first-child") | All <p> elements that are the first child of their parent |
| :first-of-type | $("p:first-of-type") | All <p> elements that are the first <p> element of their parent |
| :last-child | $("p:last-child") | All <p> elements that are the last child of their parent |
| :last-of-type | $("p:last-of-type") | All <p> elements that are the last <p> element of their parent |
| :nth-child(n) | $("p:nth-child(2)") | All <p> elements that are the 2nd child of their parent |
| :nth-last-child(n) | $("p:nth-last-child(2)") | All <p> elements that are the 2nd child of their parent, counting from the last child |
| :nth-of-type(n) | $("p:nth-of-type(2)") | All <p> elements that are the 2nd <p> element of their parent |
| :nth-last-of-type(n) | $("p:nth-last-of-type(2)") | All <p> elements that are the 2nd <p> element of their parent, counting from the last child |
| :only-child | $("p:only-child") | All <p> elements that are the only child of their parent |
| :only-of-type | $("p:only-of-type") | All <p> elements that are the only child, of its type, of their parent |
| parent > child | $("div > p") | All <p> elements that are a direct child of a <div> element |
| parent descendant | $("div p") | All <p> elements that are descendants of a <div> element |
| element + next | $("div + p") | The <p> element that are next to each <div> elements |
| element ~ siblings | $("div ~ p") | All <p> elements that are siblings of a <div> element |
| :eq(index) | $("ul li:eq(3)") | The fourth element in a list (index starts at 0) |
| :gt(no) | $("ul li:gt(3)") | List elements with an index greater than 3 |
| :lt(no) | $("ul li:lt(3)") | List elements with an index less than 3 |
| :not(selector) | $("input:not(:empty)") | All input elements that are not empty |
| :header | $(":header") | All header elements <h1>, <h2> ... |
| :animated | $(":animated") | All animated elements |
| :focus | $(":focus") | The element that currently has focus |
| :contains(text) | $(":contains('Hello')") | All elements which contains the text "Hello" |
| :has(selector) | $("div:has(p)") | All <div> elements that have a <p> element |
| :empty | $(":empty") | All elements that are empty |
| :parent | $(":parent") | All elements that are a parent of another element |
| :hidden | $("p:hidden") | All hidden <p> elements |
| :visible | $("table:visible") | All visible tables |
| :root | $(":root") | The document’s root element |
| :lang(language) | $("p:lang(de)") | All <p> elements with a lang attribute value starting with "de" |
| [attribute] | $("[href]") | All elements with a href attribute |
| [attribute=value] | $("[href='default.htm']") | All elements with a href attribute value equal to "default.htm" |
| [attribute!=value] | $("[href!='default.htm']") | All elements with a href attribute value not equal to "default.htm" |
| [attribute$=value] | $("[href$='.jpg']") | All elements with a href attribute value ending with ".jpg" |
| [attribute|=value] | $("[title|='Tomorrow']") | All elements with a title attribute value equal to 'Tomorrow', or starting with 'Tomorrow' followed by a hyphen |
| [attribute^=value] | $("[title^='Tom']") | All elements with a title attribute value starting with "Tom" |
| [attribute~=value] | $("[title~='hello']") | All elements with a title attribute value containing the word "hello" |
| [attribute*=value] | $("[title*='hello']") | All elements with a title attribute value containing the string "hello" |
| :input | $(":input") | All input elements |
| :text | $(":text") | All input elements with type="text" |
| :password | $(":password") | All input elements with type="password" |
| :radio | $(":radio") | All input elements with type="radio" |
| :checkbox | $(":checkbox") | All input elements with type="checkbox" |
| :submit | $(":submit") | All input elements with type="submit" |
| :reset | $(":reset") | All input elements with type="reset" |
| :button | $(":button") | All input elements with type="button" |
| :image | $(":image") | All input elements with type="image" |
| :file | $(":file") | All input elements with type="file" |
| :enabled | $(":enabled") | All enabled input elements |
| :disabled | $(":disabled") | All disabled input elements |
| :selected | $(":selected") | All selected input elements |
| :checked | $(":checked") | All checked input elements |
jQuery Effect Methods
| animate() | Runs a custom animation on the selected elements |
| clearQueue() | Removes all remaining queued functions from the selected elements |
| delay() | Sets a delay for all queued functions on the selected elements |
| dequeue() | Removes the next function from the queue, and then executes the function |
| fadeIn() | Fades in the selected elements |
| fadeOut() | Fades out the selected elements |
| fadeTo() | Fades in/out the selected elements to a given opacity |
| fadeToggle() | Toggles between the fadeIn() and fadeOut() methods |
| finish() | Stops, removes and completes all queued animations for the selected elements |
| hide() | Hides the selected elements |
| queue() | Shows the queued functions on the selected elements |
| show() | Shows the selected elements |
| slideDown() | Slides-down (shows) the selected elements |
| slideToggle() | Toggles between the slideUp() and slideDown() methods |
| slideUp() | Slides-up (hides) the selected elements |
| stop() | Stops the currently running animation for the selected elements |
| toggle() | Toggles between the hide() and show() methods |
jQuery HTML
- text() - Sets or returns the text content of selected elements
- html() - Sets or returns the content of selected elements (including HTML markup)
- val() - Sets or returns the value of form fields
callback function，i是当前element的index，origText是element以前的值
$("#test1").text(function(i,origText){
return "Old text: " + origText + " New text: Hello world!
(index: " + i + ")";
});
Add New HTML Content
- append() - Inserts content at the end of the selected elements
- prepend() - Inserts content at the beginning of the selected elements
- after() - Inserts content after the selected elements
- before() - Inserts content before the selected elements
Remove Elements/Content
- remove() - Removes the selected element (and its child elements)
- empty() - Removes the child elements from the selected element
jQuery Manipulating CSS
- addClass() - Adds one or more classes to the selected elements
- removeClass() - Removes one or more classes from the selected elements
- toggleClass() - Toggles between adding/removing classes from the selected elements
- css() - Sets or returns the style attribute
jQuery Dimension Methods
- width()
- height()
- innerWidth()
- innerHeight()
- outerWidth()
- outerHeight()