find class using jquery

1var myVar = $("#start").find('.myClass').val();

1$(".txtClass")                  =>  getElementsByClassName()
2
3$("#childDiv2 .txtClass")       =>  getElementById(),
4                                    then getElementsByClassName()
5
6$("#childDiv2 > .txtClass")     =>  getElementById(),
7                                    then iterate over children and check class
8
9$("input.txtClass")             =>  getElementsByTagName(),
10                                    then iterate over results and check class
11
12$("#childDiv2 input.txtClass")  =>  getElementById(),
13                                    then getElementsByTagName(),
14                                    then iterate over results and check class

1$('article a').click(function() {
2    $(this).parent().find('h3').slideToggle('fast');
3});