jQuery besic

Training Covered...
• What is jQuery?
• Why jQuery?
• How include jQuery in your web page
• Creating and manipulating elements
• Events
• Animations and effects
• Talking to the server
• jQuery UI
• Writing plugins
• Breaking news around new releases
• Using the CDN

What is jQuery?
•jQuery is an Open-Source JavaScript framework that
simplifies cross-browser client side scripting.
• Animations
• DOM manipulation
• AJAX
• Extensibility through plugins
•jQuery was created by John Resig and released 2006

Why jQuery?....
• Lightweight Footprint - Only 32kB minified and gzipped. Can
also be included as an AMD module.
• CSS3 Compliant- Supports CSS3 selectors to find elements as
well as in style property manipulation.
• Cross-Browser - IE, Firefox, Safari, Opera, Chrome, and more
• Features.
• Select and manipulate HTML
• Manipulate CSS
• JavaScript Effects and animations
• HTML DOM traversal and modification
• AJAX
• Utilities
• The heart of jQuery is “Find something then Do something”

Why jQuery?
• Example 1 -Hide an element with id "textbox“
//javascript
document.getElementById('textbox').style.display = "none";
//jQuery
$('#textbox').hide();.
• Example 2 -Create a <h1> tag with "my text“
//javascript
var h1 = document.CreateElement("h1");
h1.innerHTML = "my text";
document.getElementsByTagName('body')[0].appendChild(h1);
//jQuery
$('body').append( $("<h1/>").html("my text") ;

Enable jQuery in your page
• jQuery can be downloaded from jQuery.com.
<head>
<script src="jquery-1.11.1.min.js"></script>
</head>
• Without downloading it can be included from CDN
• Google CDN:
src=http://ajax.googleapis.com/ajax/libs/jquery/1.11.
1/jquery.min.js
• Microsoft CDN:
src=http://ajax.aspnetcdn.com/ajax/jQuery/jquery-
1.11.1.min.js
• It’s recommend to use the hosted jQuery from Google or
Microsoft.

Browser Support
Internet
Explorer
Chrome Firefox Safari Opera iOS Android
jQuery
1.x
6+
(Current -
1) or
Current
(Current -
1) or
Current
5.1+
12.1x,
(Current -
1) or
Current
6.1+ 2.3, 4.0+
jQuery
2.x
9+

Getting Started
Example:
<!DOCTYPE html>
<html>
<head>
<script
src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js">
</script>
<script>
$(document).ready(function(){
$(“#hideme").click(function(){
$(this).hide();
});
});
</script>
</head>
<body>
<p id=“hideme”>If you click on me, I will disappear.</p>
</body>
• Include jQuery in the
source file
• Define jQuery functions
• Save this file as
index.htm
• Try it!

Example : A Closer Look
• $(“#hideme") selects the element with ID hideme
• click() binds a click event to selected element
• The function executes when the click event is
fired
<script>
$(“#hideme").click(function(){
$(this).hide();
});
});
</script>
Element will be
hidden when the
element with ID
hideme is clicked

jQuery Syntax
• The jQuery syntax is used to select HTML elements and
perform some action on those element(s).
• Basic syntax: $(selector).action()
• A dollar ($) sign to define jQuery
• A (selector) to find HTML elements
• An action() to be performed on the element(s)
• Usually define functions only after the document is finished
loading, otherwise elements may not be there.
// jQuery functions go here...
});

jQuery Syntax Examples
• jQuery uses CSS syntax to select elements.
• $(this).hide()
Demonstrates the jQuery hide() method, hiding the
current HTML element.
• $("#test").hide()
Demonstrates the jQuery hide() method, hiding the
element with id="test".
• $("p").hide()
Demonstrates the jQuery hide() method, hiding all <p>
elements.
• $(".test").hide()
Demonstrates the jQuery hide() method, hiding all
elements with class="test".

jQuery Selectors
Syntax Description
$(this) Current HTML element
$("p") All <p> elements
$("p.intro") All <p> elements with class="intro"
$(".intro") All elements with class="intro"
$("#intro") The first element with id="intro"
$("ul li:first") The first <li> element of each <ul>
$("[href$='.jpg']") All elements with an href attribute that ends with ".jpg"
$("div#intro .head")
All elements with class="head" inside a <div> element
with id="intro"
For a full reference please see:
http://www.w3schools.com/jquery/jquery_ref_selectors.asp

Comparison
• Compare the following:
What are the
advantages
of the jQuery
method?
$("a").click(function(){
alert("You clicked a link!");
});
<a href="#" onclick="alert(‘You clicked a link!')">Link</a>
• Separation of structure (HTML) and behavior (JS)
• We don’t need an onclick for every element

Example
<script>
$("button").click(function(){
$("h2").hide();
});
</script> What will this do?
What happens if
you have more
than one h2?
Try it!

CSS Selectors
• jQuery CSS Selectors
• jQuery CSS selectors can be used to change CSS properties for
HTML elements.
• The following example changes the background-color of all p
elements to yellow:
• Example
• $("p").css("background-color","yellow");

jQuery Events …
• All the different visitor's actions that a web page
can respond to are called events.
• moving a mouse over an element
• selecting a radio button
• clicking on an element
Mouse Events Keyboard Events Form Events Document/Window Events
click keypress submit load
dblclick keydown change resize
mouseenter keyup focus scroll
mouseleave blur unload

jQuery Events
Event Method Description
$(selector).click(function)
Invokes a function when the selected
elements are clicked
$(selector).dblclick(function)
elements are double-clicked
$(selector).focus(function)
elements receive the focus
$(selector).mouseover(function)
Invokes a function when the mouse is over
the selected elements
$(selector).keypress(function)
Invokes a function when a key is pressed
inside the selected elements
For a full jQuery event reference, please see
http://www.w3schools.com/jquery/jquery_ref_events.asp Reference

Example
<script>
$("#p1").mouseenter(function(){
alert("You entered p1!");
});
});
</script>
What action will be
executed when
mouse enter on
element with id p1??
Try it!
$("p").click(function(){
// action goes here!!
});

Manipulating CSS
CSS Properties Description
$(selector).css(propertyName)
Get the style property value of the first
selected element
$(selector).css(propertyName,value)
Set the value of one style property for
selected elements
$(selector).css({properties})
Set multiple style properties for
selected elements
$(selector).addClass(class)
Apply style class to the selected
elements
full jQuery CSS reference: http://www.w3schools.com/jquery/jquery_ref_css.asp
For more on the css function, see : http://api.jquery.com/css/

Example
<script>
$("#btnColor").click(function(){
$("#lemon").addClass("blue");
});
</script>
Change color of paragraph lemon
when btnColor is clicked
<style type="text/css">
.red{
color:red;
}
.blue{
color:blue;
}
</style>

Example
Display the color of the
paragraph lemon when
btnColorCheck is clicked.
What color is the paragraph?
<script>
$("#btnColorCheck").click(function(){
alert($("#lemon").css("color"));
});
</script>

jQuery Effects
Function Description
$(selector).hide() Hide selected elements
$(selector).show() Show selected elements
$(selector).toggle() Toggle (between hide and show) selected elements
$(selector).slideDown() Slide-down (show) selected elements
$(selector).slideUp() Slide-up (hide) selected elements
$(selector).slideToggle() Toggle slide-up and slide-down of selected elements
$(selector).fadeIn() Fade in selected elements
$(selector).fadeOut() Fade out selected elements
$(selector).fadeTo() Fade out selected elements to a given opacity
$(selector).fadeToggle() Toggle between fade in and fade out
$(selector).fadeToggle() To stop an animation or effect before it is finished.
Hide, Show, Toggle, Slide, Fade, and Animate element in jQuery effect.

Example
<script>
$("#flip").click(function(){
$("#panel").slideToggle("slow");
});
</script>
Create a toggle button
that shows/hides
paragraph lemon.

Example
<script>
$("div").animate({left:'250px'});
});
});
</script>
create custom
animations. for html
element div

Manipulating HTML …
• Set and get Content and Attributes:
• text() - Sets or returns the text content of selected elements
• html() - Sets or returns the content of selected elements (including
HTML markup)
• val() - Sets or returns the value of form fields
• Add Elements
• append() - Inserts content at the end of the selected elements
• prepend() - Inserts content at the beginning of the selected
elements
• after() - Inserts content after the selected elements
• before() - Inserts content before the selected elements

Example
<script>
$("#w3s").attr("href","http://www.w3schools.com/jquery");
});
});
</script>
change (set) the value of
the href attribute in a link

Example
<script>
$("#btn1").click(function(){
$("p").append(" <b>Appended text</b>.");
});
$("#btn2").click(function(){
$("ol").append("<li>Appended item</li>");
});
});
</script>
inserts content AT THE
END of the selected
HTML elements.

Manipulating HTML …
• Remove Elements:
• remove() - Removes the selected element (and its child
elements)
• empty() - Removes the child elements from the selected
element
• Get and Set CSS Classes
• addClass() - Adds one or more classes to the selected
elements
• removeClass() - Removes one or more classes from the
selected elements
• toggleClass() - Toggles between adding/removing classes
from the selected elements
• css() - Sets or returns the style attribute.

Example
<script>
$("#div1").remove();
});
});
</script>
remove elements and
content.

Example
<script>
$("h1,h2,p").addClass("blue");
$("div").addClass("important");
});
});
</script>
Add class attributes to
different elements.

Manipulating HTML ….
• jQuery - Dimensions
• width()
• height()
• innerWidth()
• innerHeight()
• outerWidth()
• outerHeight()

Example
<script>
var txt="";
txt+="Width of div: " + $("#div1").width() + "</br>";
txt+="Height of div: " + $("#div1").height();
$("#div1").html(txt);
});
});
</script>
Display di width and
height.

Manipulating HTML
$(selector).html(content)
Changes the (inner) HTML of selected
elements
$(selector).append(content)
Appends content to the (inner) HTML of
selected elements
$(selector).after(content) Adds HTML after selected elements
For a full jQuery HTML reference, please see jQuery HTML Methods Reference

Manipulating HTML
$(selector).hide() Hide selected elements
$(selector).show() Show selected elements
$(selector).toggle() Toggle (between hide and show) selected elements
$(selector).slideDown() Slide-down (show) selected elements
$(selector).slideUp() Slide-up (hide) selected elements
$(selector).slideToggle() Toggle slide-up and slide-down of selected elements
$(selector).fadeIn() Fade in selected elements
$(selector).fadeOut() Fade out selected elements
$(selector).fadeTo() Fade out selected elements to a given opacity
$(selector).fadeToggle() Toggle between fade in and fade out
$(selector).fadeToggle() To stop an animation or effect before it is finished.
Hide, Show, Toggle, Slide, Fade, and Animate element in jQuery effect.

Example 10
<script>
$("#btnReplace").click(function(){
$("#lemon").html("Lollipop soufflé ice
cream tootsie roll donut...");
});
</script>
Replace text in
paragraph lemon when
btnReplace is clicked.

Ajax
• The jQuery $.post() method loads data from the server using
an HTTP POST request.
• Syntax
$.post(URL, {data}, function(data){…});
$.post("myScript.php", {name:txt}, function(result) {
$("span").html(result);
});
ajax.php
Parameter Description
URL Required. Specifies the url to send the
request to.
data Optional. Specifies data to send to the
server along with the request.
function(data) •Optional. Specifies a function to run if
the request succeeds.
data - contains the resulting data from
the request
http://www.w3schools.com/jquery/ajax_post.asp

Ajax
<?php
$id = $_POST['id'];
mysql_connect("localhost", "omuser", "omuser") or die("Error connecting");
mysql_select_db("om") or die("Error selecting DB");
$query = "SELECT * FROM items WHERE item_id = $id";
$result = mysql_query($query);
if (mysql_num_rows($result) == 0) {
echo "Product ID $id not found.";
return;
}
$row = mysql_fetch_array($result);
echo "<strong>Item ID:</strong> {$row['item_id']}<br>";
echo "<strong>Title:</strong> {$row['title']}<br>";
echo "<strong>Artist:</strong> {$row['artist']}<br>";
echo "<strong>Price:</strong> {$row['unit_price']}<br>";
Get this from the Ajax call
show_product.php

Ajax
$('#show').click(function(){
var prodId = $('#id').val();
$.post(
"show_product.php",
{id:prodId},
function(result) {
$('#detail').html(result);
}
);
});
When the button is clicked
Get the text box value
Name of the PHP script
The key/value to be passed
Update the "detail" div
With the output of the PHP script
Ajax POST
ajax.php

Resources
• http://jquery.com/
• http://www.w3schools.com/jquery
• http://jqueryui.com/
Md. Syeful Islam
Sr. Software Engineer
Samsung R&D Institute Bangladesh
Email: syefulislam@yahoo.com
Skype: syeful_islam

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