I found the solution to invoke client side event using jquery
$(document).ready(function() {
$(".rootNode").live("click", function() {
});
$(".childNode").live("click", function() {
});
$(".rootwithoutchild").live("click", function() {
});
});
I could not add event for the specific node in the server side while looping through as I don't find any option to add attributes for the Treenode. So I have tried using jquery and finally achieved.
Thanks for you help