javascript - selecting all elements of a class within elements of given id -

my html code looks

<div id="parta">     <div class="myclass typea"> blabla </div>     <div class="myclass typea"> blabla </div>     <div class="myclass typea"> blabla </div>     <div class="myclass typeb"> blabla </div> </div>  <div id="partb">     <div class="myclass typea"> blabla </div>     <div class="myclass typea"> blabla </div>     <div class="myclass typea"> blabla </div>     <div class="myclass typeb"> blabla </div> </div> 

i want use javascript count number of elements of class myclass, 1 within #parta.
when use
$(".myclass").size()
8 result (it counts elements both parta , partb).
when use
$(".myclass.typea").size()
6 (it gets myclass , typea elements, both parts)
when use
$("#parta.myclass").size()
0.
apparently, javascript command looks elements have both id=parta , class=myclass. possible reformulate command in order count number of myclass class contained within elements id=parta?

thanks lot!

you're missing space in 1 of selectors. try:

$("#parta .myclass").size() 

alternatively do:

$('#parta').find('.myclass').length; 

or

var parta = $('#parta'); $('.myclass', parta).length;