How does jQuery get elements

JQuery uses a method called $(selector) to get action elements on a page. Selector takes strings or arrays of elements

Select expressions using CSS selectors or jquery-specific expressions:

//CSS selector $(document) // select the entire document object $('#myId') // select the web element $('div. MyClass ') // select the div element whose class is myClass $('input[name=first]') $('input[name=first]') $('a:first') $('tr:odd' $('#myForm :input') $('div:visible') $('div:gt(2)') Except for the first three $('div:animated') // select the div element that is currently animatedCopy the code

How is jQuery chained

One of the design ideas of JQuery is that it uses an idea called chain programming. Once you take an element, you can perform a series of operations on it, and all of these operations can be connected, like a chain of execution. Such as $(‘ div ‘). The find (‘ a ‘). Eq. (2) the HTML () ‘go’

How does jQuery create elements

JQuery has wrapped the creation element, we can just pass in the HTML string, jQuery will automatically create the node for us. Such as:

$(`
<div>
	<span class="red">
		this is new node
	</div>
</div>`)
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How does jQuery move elements

JQuery provides four teams of methods for manipulating the position of elements in a web page

.insertafter () 'and.after() : outside the existing element, insert elements.insertbefore () and.append() : outside the existing element, insert elements.appendto () and.append() from the front: Inside the existing element, insert elements from behind. PrependTo () and. Prepend () : Inside the existing element, insert elements from the frontCopy the code

How does jQuery modify an element’s attributes

JQuery provides several methods to modify the attributes of an element:

/ / tag attributes to add and delete $(' # div.) attr (' class ') / / $(' # div.) attr (' class ', 'red') / / increase and change; If there is a modification, If you don't have is add $(' # div.) removeAttr (' class ') / / delete / / the class add $(' # div.) addClass (' red ') / / to add $(' # div). RemoveClass (' red ') / / delete $('input[name="username"]').val()Copy the code

reference

  1. JQuery design and implementation