Jquery $of hashform: the difference between input and $of hashform input

$("form :input") returns all the form objects in the form, including the textarea, select, button, and so on
$("form input") returns all input tag objects in the form

Form input is a hierarchical selector (returns all the elements to which each selector matches)
Form :input belongs to the form selector (matches all < Input> , < Textarea> , < Select> , < Button> Elements)