1.Login to your blogger dashboard.
2.Go to--> layout- -> Edit HTML
3.Scroll down to where you see <head> tag.
4.Now copy below code and paste it just after <head> tag.
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript"></script>
5.Click on "Save Templates" and now you are done.
What is the purpose of JQuery on bloggers ???