jQuery :checkbox Selector

$( ":checkbox" ) is equivalent to $( "[type=checkbox]" ). As with other pseudo-class selectors (those that begin with a ":") it is recommended to precede it with a tag name or some other selector; otherwise, the universal selector ("*") is implied. In other words, the bare $(':checkbox') is equivalent to $( "*:checkbox" ), so $( "input:checkbox" ) should be used instead.