Techno WeBlog

Recently I have faced an issue with session in IFrames in IE Browsers. The issue is like session is not sharing between pages inside iframe particularly if you are accessing it in a different domain. The script will run smoothly without the iframe, but when i use the iframe in IE and safari it doesn’t work properly. This is because cross site scripting(XSS)

IE is very particular when it comes to “cross-site/cross-directory” linking in iFrames and sessions. If the iFrame contains or calls a script from a different directory then IE does not always pass the session header information. If the contents are called from another domain then absolutely it will not work.

I have eliminated the issue with some workaround. My workaround is as follows.

1. If you notice the iframe SRC in IE browser, you can see that the URL is not modifying when you move to another page. It will remain as it is and you will not be able to pass any new parameter. I have take this as an advantage and created one token and append it to the initial SRC. It is as follows.

   <iframe src=”http://www.example.com/?token=<?php echo md5(uniqueid()); ?>” > </iframe>

2. I have created a table for storing session and top of each page i am checking whether the token is exist in database. If it is not exist i am inserting it as a new entry in table. Here token is primary key and session is storing as a serialized object using php serialization function.
3. In each page i will get the same token from iframe src and i am checking the same exist in db. If exist in db fetch the serialized session, unserialize it and assign back to session.

I don’t know is there any other good solution exists other than this.

Filed under: Security, PHP | No Comments »

HTML5 is introducing a new feature called “Storage Tables”. With “Storage Tables” can be described as a simple database in the browser. This allows you to store and retrieve a value even when the user has closed his browser and reopened it.

Like session HTML storage is in server and it is more useful because it doesn’t get sent to the server (less overhead), and because the fields can contain more information than a cookie.

Currently, although in theory there’s little difference with cookies, HTML5 Storage is more useful because it doesn’t get sent to the server (less overhead), and because the fields can contain more information than a cookie (this feature is untested, BTW). These two advantages are clearest when you want to set a lot of values; for instance for a preference menu.

So what is the difference between localStorage and sessionStorage

Basically sessionStorage sets fields on the browser window. When the window is closed, the session fields are lost, even if the site remains open in another window.

localStorage sets fields on the domain. Even when you close the browser, reopen it, and go back to the site, it remembers all fields in localStorage. The interesting part is that if you change a localStorage field this event fires in all windows that contain a page of your site.

Essentially, that means that the entire sessionStorage is cleared when the user closes the browser window, while localStorage will remain available forever.

PPK has written an article about this. You can find it here: http://www.quirksmode.org/blog/archives/2009/06/html5_storage_t.html

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Filed under: HTML | No Comments »

  Out of all the Internet buzzwords and jargon that have made the transition to the public consciousness, “Web 2.0″ might be the best known. Even though a lot of people have heard about it, not many have any idea what Web 2.0 means. Some people claim that the term itself is nothing more than a marketing strategy designed to convince venture capitalists to invest millions of dollars into Web sites. When Dale Dougherty of O’Reilly Media came up with the term, there was no clear definition. There wasn’t even any agreement about if there was a Web 1.0.

In brief, the characteristics of Web 1.0, 2.0, and most discussing 3.0 is as follows.

Web 1.0 - That Geocities & Hotmail era was all about read-only content and static HTML websites. People preferred navigating the web through link directories of Yahoo! and dmoz.

Web 2.0 - This is about user-generated content and the read-write web. People are consuming as well as contributing information through blogs or sites like Flickr, YouTube, Digg, etc. The line dividing a consumer and content publisher is increasingly getting blurred in the Web 2.0 era.

Web 3.0 - This will be about semantic web (or the meaning of data), personalization (e.g. iGoogle), intelligent search and behavioral advertising among other things.

This slide neatly sums up the main differences between Web 1.0, Web 2.0 and Web 3.0.

If you interested and like to know more about web 3.0 check http://www.labnol.org/internet/web-3-concepts-explained/8908/

Also check a presentation by Tim Berners-Lee on the next Web. Tim Berners-Lee invented the World Wide Web. He leads the
World Wide Web Consortium, overseeing the Web’s standards and development.
http://www.ted.com/index.php/talks/lang/eng/tim_berners_lee_on_the_next_web.html

Filed under: Web, Social Media | 1 Comment »

One of the most powerful features of CSS is the cascading. Knowing how a browser chooses and applies your styles is invaluable knowledge. There are various methods to apply css to an element.

External Style Sheets - All css will written in separate file and include in html
Embedded Style Sheets - write all css in a <style > </style > block in the html page.
Inline Styles - In the html tag we will specify the css like style=”color:red”

Inline styles have the highest priority of all CSS. In general, we should not avoid using them and place your CSS declarations in external files. However, sometimes it is not possible.

Fortunately, there is a way to override inline styles from an external stylesheet:

strong[style] { color: blue !important; }

This will force the text in the strong tag to become blue in the page. The method appears to work in all major browser, including:

Internet Explorer 8.0
Mozilla Firefox 2 and 3
Opera 9
Apple Safari, and
Google Chrome
Internet Explorer 6 and 7 are the notable exceptions. However, this technique is not something you should use on a day-to-day basis. Keep your CSS clean and only override inline styles when there is absolutely no alternative.

More Details: http://www.sitepoint.com/blogs/2009/05/27/override-inline-css/

Filed under: Css | No Comments »

Google Internet Bus
Posted on February 3rd, 2009 by admin | Edit

Google India has a launched a very unique initiative to educate the offline population in India about the benefits of Internet.

The project is called The Internet Bus. The aim of this project is an attempt educate people about what the Internet is, and how it may be beneficial to their lives, by taking the Internet experience to them through a customised Internet-enabled bus, which will travel to several towns and cities across India.

To view more pictures : http://photos.codlib.com/2009/02/03/google-internet-bus/

To view more pictures : http://photos.codlib.com/2009/02/03/google-internet-bus/

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Filed under: Announcements, Google | No Comments »