jQuery

 What is jQuery?

jQuery is a lightweight JavaScript library that emphasizes interaction between JavaScript and HTML

 What does dollar Sign ($) means in JQuery?

 Dollar Sign is nothing but it's an alias for JQuery.

$(document).ready(function(){

});

Over here $ sign can be replaced with "jQuery " keyword.
 jQuery(document).ready(function(){

});

Why is jQuery better than javascript? 

jQuery is great library for developing ajax based application.
It helps the programmers to keep code simple and concise and reusable

Which sign does jQuery use as a shortcut for jQuery? 

$(dollar) sign.

Is jQuery a library for client scripting or server scripting?

Client scripting

Is jQuery a W3C standard?

No

What are jQuery Selectors?

Selectors are used in jQuery to find out DOM elements. Selectors can 
find the elements via ID, CSS, Element name and hierarchical position of
the element. 

What is the name of jQuery method used for an asynchronous HTTP request? 

jQuery.ajax()

How is body onload() function is different from document.ready() function

used in jQuery? 

 Document.ready() function is different from body onload()function 

because off 2 reasons.
1. We can have more than one document.ready() function in a page 

where we can have only one onload function.
2. Document.ready() function is called as soon as DOM is loaded 

where body.onload() function is called when everything gets loaded on

the page that includes DOM,images & all associated resources of the page.

What are features of JQuery or what can be done using JQuery? 

Features of Jquery
1. One can easily provide effects and can do animations.
2. Applying / Changing CSS.
3. Cool plugins.
4. Ajax support
5. DOM selection events
6. Event Handling 

Name some of the methods of JQuery used to provide effects?

Some of the common methods are :
1. Show()
2. Hide()
3. Toggle()
4. FadeIn()
5. FadeOut()