jQuery - Selectors

You can select an element with jQuery by using one of three selectors: by tag ID (#), by tag TYPE (DOM element), and by CSS Class.

$("#demo1").hide();                 // id
$("H1").hide();                     // element
$(".special-class").hide();         // css class

More Examples of jQuery Selectors:

$("*")				    Selects all elements
$(this)				    Selects the current HTML element
$("p.intro")			Selects all <p> elements with class="intro"
$("p:first")			Selects the first <p> element
$("ul li:first")		Selects the first <li> element of the first <ul>
$("ul li:first-child")	Selects the first <li> element of every <ul>
$("[href]")			    Selects all elements with an href attribute
$("a[target='_blank']")	Selects all <a> elements with a target attribute value equal to "_blank"
$("a[target!='_blank']")Selects all <a> elements with a target attribute value NOT equal to "_blank"
$(":button")			Selects all <button> elements and  elements of type="button"
$("tr:even")			Selects all even <tr> elements
$("tr:odd")			    Selects all odd <tr> elements
$(":empty")			    Selects empty elements - an element without child elements or text.
$(":disabled")			Selects all elements with a disabled property.