Java script202

Java script202

• 1.
  JavaScript By Dr. Ejaz Ahmed
• 2.
  Scripting Language Javascript •JavaScript was designed to add interactivity to HTML pages • JavaScript is a scripting language • A scripting language is a lightweight programming language • JavaScript is usually embedded directly into HTML pages • JavaScript is an interpreted language (means that scripts execute without preliminary compilation) • Everyone can use JavaScript without purchasing a license
• 3.
  Are Java andJavaScript the same? • NO! • Java and JavaScript are two completely different languages in both concept and design! • Java (developed by Sun Microsystems) is a powerful and much more complex programming language - in the same category as C and C++. • JavaScript was invented by Brendan Eich at Netscape (with Navigator 2.0), and has appeared in all browsers since 1996.
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  Introduction • JavaScript was designed to add interactivity to HTML pages. • JavaScript is a scripting language. • JavaScript is usually embedded directly into HTML pages. • JavaScript is an interpreted language (means that scripts execute without preliminary compilation). • It is an event-driven language. • To insert a JavaScript into an HTML page, use the <script> tag. • Inside the <script> tag use the type attribute to define the scripting language. • The <script> and </script> tells where the JavaScript starts and ends. <script type="text/javascript">
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  How to usejavascript? • The common way to use the javascript is as follows; • Define some HTML tag with ID attribute value given. • In that HTML tag add/call the function statement and bind it to some event on which you want to invoke the javascript function (event handler). • Write the said function (event handler) between <script> and </script> tags. • When the page downloads, your handler will be called on event you described within the HTML tag.
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  What can aJavaScript do? • JavaScript gives HTML designers a programming tool - HTML authors are normally not programmers, but JavaScript is a scripting language with a very simple syntax! Almost anyone can put small "snippets" of code into their HTML pages • JavaScript can put dynamic text into an HTML page - A JavaScript statement like this: document.write("<h1>" + name + "</h1>") • can write a variable text into an HTML page • JavaScript can react to events - A JavaScript can be set to execute when something happens, like when a page has finished loading or when a user clicks on an HTML element • JavaScript can read and write HTML elements - A JavaScript can read and change the content of an HTML element • JavaScript can be used to validate data - A JavaScript can be used to validate form data before it is submitted to a server. This saves the server from extra processing
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  Ajax • AJAX =Asynchronous JavaScript and XML. • AJAX is not a new programming language, but a new way to use existing standards. • AJAX is the art of exchanging data with a server, and update parts of a web page - without reloading the whole page. • AJAX allows web pages to be updated asynchronously by exchanging small amounts of data with the server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page. • Classic web pages, (which do not use AJAX) must reload the entire page if the content should change. • Examples of applications using AJAX: Google Maps, Gmail, Youtube, and Facebook tabs.
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  How Ajax Works?
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  Web Servers • jakarta-tomcat-5.0.28 (with jdk) • Dot Net (.Net) Framwork • IBM WebSphere • ZendCore • etc.
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  Getting Started withJavaScript Event: onclick
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  Introducing document ‘getElementById()’ method
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  Validation Through JavaScript
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  Example
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  Example …
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  Example – Dataconversions and Calculations
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  Example – DialogueBox & Pop up Window
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  Code - DialogueBox & Pop up Window
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  Example – DialogueBox & Calculations
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  Pop up windowand Document Write
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  HTML JavaScript Arrays