jquery selector document and class code example
Example 1: jquery class selector
$('.class').jquery_function();
Example 2: jquery find tag and class
$(".txtClass") => getElementsByClassName()
$("#childDiv2 .txtClass") => getElementById(),
then getElementsByClassName()
$("#childDiv2 > .txtClass") => getElementById(),
then iterate over children and check class
$("input.txtClass") => getElementsByTagName(),
then iterate over results and check class
$("#childDiv2 input.txtClass") => getElementById(),
then getElementsByTagName(),
then iterate over results and check class