What jQuery? Why jQuery? Advantages ? Disadvantages ?

What is jQuery?

•  jQuery is a lightweight, "write less, do more",

   JavaScript library.

• The purpose of jQuery is to make it much easier

   to use JavaScript on your website.

Why jQuery?

•  There are lots of other JavaScript frameworks out there, but       jQuery seems to be the most popular, and also the most               extendable.

• Many of the biggest companies on the Web use jQuery, such as:

•  Google

•  Microsoft

•  IBM

•  Netflix

The jQuery library contains the following feature

• HTML/DOM manipulation

• CSS manipulation

• HTML event methods

• Effects and animations

• AJAX

• Utilities

jQuery Syntax

• Basic syntax is: $(selector).action()

• A $ sign to define/access jQuery

Examples:

• $(this).hide() - hides the current element.

• $("p").hide() - hides all <p> elements.

• $(".test").hide() - hides all elements with class="test".

• $("#test").hide() - hides the element with id="test".

Advantages of jQuery

• Ease of use

• jQuery uses a simple, clean, powerful syntax

• Makes a website look more professional

• Strong open source community

• Lots of plugins available.

• Large library

• jQuery is highly extensible

• Ajax support

Disadvantages  of jQuery

• Functionality maybe limited

• JQuery javascript file required

The Document Ready Event

    • $(document).ready(function(){
     // jQuery methods go here...
});

• jQuery Selectors

–   jQuery selectors allow you to select and manipulate HTML element(s).

–   jQuery selectors are used to "find" (or select) HTML elements based on their id, classes, types, attributes, values of attributes and much more. It's based on the existing CSS Selectors, and in addition, it has some own custom selectors.

• All selectors in jQuery start with the dollar sign and parentheses: $().

• The element Selector

– The jQuery element selector selects elements based on the element name.

– You can select all <p> elements on a page like this: $("p")

jQuery Effects - Hide and Show

•Syntax:

•$(selector).hide(speed);

–hide()

•$(selector).show(speed);

–show()

jQuery Stop Methods

•stop()

jQuery Fading Methods

• With jQuery you can fade an element in and out of visibility.

• jQuery has the following fade methods:

• fadeIn()

• fadeOut()

• fadeToggle()

• fadeTo()

jQuery Sliding Methods

• With jQuery you can create a sliding effect on elements.

• jQuery has the following slide methods:

• slideDown()

• slideUp()

• slideToggle()