Is jQuery is a new technology?
Definitely not, jQuery is a new approach to simplify client side web development like the HTML traversing with DOM and Ajax manipulation.
Download jQuery Library
The latest version of jQuery can be downloaded from the jQuery official website.
TEST RUN IT!
<title>jQuery Hello World</title>
$("#msgid").html("This is Hello World by JQuery");
This is Hello World by HTML
<div id="msgid"> </div>
The $() indicate a jQuery syntax, and the script means when DOM elements are fully loaded, execute the jQuery script to dynamically create message and append it to the html tag id "msgid".