Selects all elements that are the first among siblings of the same element name. The :first-of-type

Selects all input, textarea, select and button elements. The :input selector basically

Selects the element that is the root of the document. In HTML, the root of the document, and thus

Selects all elements of the specified language. The :lang() selector matches elements

Selects all elements that are the nth-child of their parent. Because jQuery's implementation of

Selects elements that have the specified attribute with a value exactly equal to a certain value.

Selects all elements of type radio. $( ":radio" ) is equivalent to $( "[type=radio]"

Selects all elements that are descendants of a given ancestor. A descendant of an element could

Selects all elements that are the first child of their parent. While

Selects all elements of type checkbox. $( ":checkbox" ) is equivalent to $( "[type=checkbox]"