1 $() vs $

$("someSelector") returns a array. This is defiend in jQuery.prototype.

$.methodName is a method defined in jQuery...

2

methods below will stop the jQuery to manipulate the DOM until the document or window is ready...

the differences between them is, document just considerate the DOM, and window will considerate the whole page, this means until the waiting circle stops~

$(document).ready( // here comes lots of functions);

$(window).ready( // here comes lots of functions);

3 Conflicts 

var $j = jQuery.noConflict();

will make the $("...") the same as $j("...") in order to avoid conflicts from other liberaries also with an alias $...

4 Attribute

setter

$("selecteor").attr("someAttribute", someObject);

getter

$("selecteor").attr("someAttribute");

$( "a" ).attr( "href" ); // Returns the href for the first a element in the document

5 Prseudo-selector

When using the :visible and :hidden pseudo-selectors, jQuery tests the actual visibility of the element, not its CSS visibility or display properties.

jQuery looks to see if the element‘s physical height and width on the page are both greater than zero.

6 manipulating the DOM elements

.insertAfter()  VS .after().

.insertBefore() VS .before()

.appendTo() VS .append()

.prependTo() VS .prepend()

.remove() the selected elements will removed from the page, do returns something, but they are barely useless.

.detach() the selected elements will removed from the page, and this method will return something useful...

.empty() this method is used to the parent element in order to remove the children nodes~

7 create new elements

a : $("<p>This is a P</p>");

b :