Use of Jquery filter (first, last, not, even, odd)_jquery

$(function(){
$(" #menu li:first").click(function(){
$(this).addClass("b");
});
$("#menu li:last").text ("last");//Insert the text "last" into the last li element in the li list with the id of menu
$("#menu li:first").text("first");//li list Insert the text "first" into the first li element
$("#menu li:not(.on)").text("on");//The style in the li list is not class="on" The li element inserts text "on"
$("#menu li:even").text("odd row");
$("#menu li:odd").text("even row") ;
});