Posted by iphp on Jun 16, 2009 in
javascript Since its birth in 1994, Javascript has come a long way. Today it is one of the most popular programming languages on the web. Javascript has been on the rise and is growing faster since AJAX based applications reignited professional developer interest. It is now possible to it to write applications on the server, the mobile devices, on the browsers (add ons and plugins), inside PDF documents, even in some remote controls and many more to come.
Javascript application development in Mobile devices
Build Native Applications using Javascript
Palm’s new OS is the first mobile platform to be built from the ground up to combine standard technology, innovation and integration. At its core, webOS leverages several industry-standard technologies, including web technologies such as CSS, XHTML and JavaScript. You can think of webOS applications as native applications, but built from the same standard HTML, CSS and JavaScript that you’d use to develop web applications. Palm has extended the standard web development environment through a JavaScript framework that gives standardized UI widgets, and access to selected device hardware and services.
Javascript can be used on the iphone too. The HTML 5 specification provides a new mechanism for client-side data storage: JavaScript database support. This feature shipped originally with iPhone OS 2.1. When you use “Add to Home Screen” from the “+” button on Safari for iPhone, a web application with a manifest defined (per the HTML5 spec) will be saved with any cached resources. It is also worth noting that these features have not been added to Safari on Mac OS X or Windows.
Desktop Application development using Javascript
Adobe AIR is a cross-platform desktop runtime created by Adobe that allows web developers to use web technologies to build and deploy Rich Internet Applications (RIAs) and web applications to the desktop. This means what you can write you application using Javascript and then let AIR to figure out how to run your code in Windows, Linux, Mac and future operating systems.
Desktop App using Javascript
The application shown in the pic is written using Javascript, HTML and CSS. It uses the ExtJS library. Javascript can be used to dock the application in the taskbar, delete and modify files on the hard drive, communicate to different server, use AJAX, etc. You can even use flash within your app to make the application look and feel much better. This gives the web developer good access to a desktop.
Server side Scripts using Javascript
Server side JavaScript has been around for a long time and potentially offers some unique and interesting advantages over other languages (like PHP, ASP, etc) because the same language is spoken by both client and server. There are numerous attempts to bring server side javascript to the masses. Server side Javascript has to do much more than what it has to do at the browser level with access to databases, files, and networking, as well as logging, process management, scalability, security, integration APIs, and extensibility. You can even use your own javascript libraries on the server jQuery, dojo, Ext JS, prototype, etc.
Javascript in other places
- Adobe reader (from v3.02) supports Javascript for forms and basic operations. SOAP support has also been included since version 7.0. There is also access to the entire 3D Javascript API. More details on using Javascript is available here
- Open office application suite supports Javascript to write macros. This move looks like a sensible addon given the usage of VBScript in MS Office suite.
- Apple’s Dashboard Widgets, Microsoft’s Gadgets, Yahoo! Widgets, Google Desktop Gadgets are implemented using JavaScript.
- The oddest one in this list will have to be the Philips Remote Control which uses Javascript
ECMAScript 4 (ECMAScript Harmony)
Javascript has been relatively stable since the third edition of ECMAScript published in 1999. Features under discussion for a future edition originally ECMAScript 4 now ECMAScript Harmony include Classes, a module system, static typing and Optional type annotations, Generators, Iterators, Destructuring assignment, algebraic data types. Well if you think this is ambitious you should see the original ECMAScript 4 which had more semantic and syntactic innovation. Packages, namespaces and early binding from ECMAScript 4 are no longer included for planned releases with ECMAScript Harmony. The intent of these features is partly to better support “programming in the large”, and to let programmers sacrifice some of the script’s ability to be dynamic for performance.
So yes as a web developer who uses Javascript on a daily basis, I am excited to watch Javascript grow and be available in more places.
Tags: javascript, Web
Posted by php-manual on Mar 18, 2009 in
Web Around 80% of the end-user response time is spent on the front-end. A fair share of this time is spent on downloading components of the page like scripts, Flash, stylesheets, images etc. Javascript takes majority of the loading time of a webpage because scripts block parallel downloading and rendering in the page. Even if you do not have a lot of Javascript files to load on your webpage they can still block loading other content on your page while they load. Lets have a look at how the standard javascript file include method and the script DOM element method in detail below.
Standard Javascript file include method
<SCRIPT src="A.JS" language="JavaScript/text"></SCRIPT>
<SCRIPT src="B.JS" language="JavaScript/text"></SCRIPT>
<IMG src="1.GIF" />
<IMG src="2.GIF" />
<IMG src="3.GIF" />
Javascript blocks the other elements from loading (Example)
Script DOM element method
var p = g.getElementsByTagName("HEAD")[0];
var c = g.createElement("script");
c.type= "text/javascript";
c.onreadystatechange = n;
c.onerror = c.onload = k;
c.src = e;
p.appendChild(C);
Javascript executed without blocking any element from loading
This method creates a DOM element for each Script and then adds the element to the HTML.
NOTE:
1) Only when the appendChild function is called the Javascript will be executed.
2) For inlined code that depends on the Javascript and also for a similar method of Asynchronous Script Loading - See Steve Souders blog
3) If you go to MSN.com (Alexa top 10 site based on traffic) and hit view source you can see the javacript elements are included by using the script dom element to load the web pages faster. This is a good example of where you can use the script dom element method for certain js files that do not have inlined code dependency. Let us run a Pagetest waterfall report and you can see the following for MSN.COM
Pagetest Waterfall report of MSN.COM shows no blocking during page load
Tags: javascript, performance, Web
Posted by php-manual on Jan 19, 2009 in
PHP,
Security,
Web We all do our best to write excellent code and also keep our installations of popular open source tools like Wordpress, Joomla, Oscommerce, Drupal, phpmyadmin and all its plugins always updated to prevent any attack or hackers using known exploits on them. This article is not aimed at going through all those methods to help you secure your website BUT focuses on how to send you an alert once your website is hacked and running “hidden” code that you didnt write.
Read more…
Tags: hash, PHP, Security, Web, webserver
Posted by php-manual on Jan 16, 2009 in
Web We have all been doing email address validation for a very long time to make sure that the email is correctly formatted. This is to avoid users entering wrongly formatted email address but still they can accidentally give us a wrong email address.
Example of a correctly formatted email address but still wrong:
mailbox.does.not.exist@reddit.com [VALID email fromat but still not correct]
Above case specifically happens when you take important customer email on phone and you type in the wrong email. So is there a QUICK solution to really check the email without sending a test message to the user? Yes.
Read more…
Tags: forms, mail, PHP, Web
Posted by php-manual on Jan 14, 2009 in
Web What is CAPTCHA?
CAPTCHA is an acronym for “completely automated public Turing test to tell computers and humans apart.” This can be with images / audio or whatever we will see in future.
Why do sites use it?
CAPTCHA is used to prevent bots from automatically submitting forms with SPAM or other unwanted content. Google and other companies use it to prevent bots from creating multiple Gmail accounts.
What is wrong with it?
Users will have to enter this additional information every time they have to submit a form. This is getting more and more difficult to decode for humans as the bots are getting better at it. I am sure that everyone reading this post has atleast once got a CAPTCHA entered wrongly.
Alternative Simple soultion:
NOTE: Does not apply for highly targeted sites like gmail, yahoo mail and others alike.
However,
If you have a sales form which requires an entry of username, email and phone number for a call back
OR
a simple contact us form with just name, number, description.
1) Have server validation of data.
All the forms have only client validation in javascript. Just validate in server and you can have 70% of spam bot submissions caught.
EG: If your form has Name, Email, Telephone.
The bot will send some 500 character text in Name and valid email and some random data in phone field. A simple validation on the server to trash Name having more than 30 characters will do the trick.
2) Hidden input element
Add an extra text input element to your form. In an external style sheet you set the element to display: none; thus making it invisible to all users with CSS enabled. Spam bots will usually fill all fields in a form you know that any forms submitted where this invisible field is not empty are spam.
With the above two simple steps you can see that most sites can avoid spam messages and still not having to use a captcha.
So in short - for all the websites with simple contact forms why do we use CAPTCHA and risk giving the customer an additional field to fill and risk not to getting them to fill it at all ??
Tags: captcha, forms, Web
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