PAYAL: February 2011

Wednesday, February 23, 2011

10 ways to make your web site more accessible

Ten of the most important improvements and modifications webmasters can make to improve the accessibility of their sites to people with disabilities or special needs. The team looked at 500 sites in 18 countries were tested with XValid in all.
They were then able to analyze the data they accrued and to work out ten minimal guidelines for making web sites more accessible to everyone. The researchers suggest that the issue of ensuring equitable access for all regarding age and ability will become increasingly important as we become increasingly dependent on the world wide web as a source of information and knowledge.
The team suggests that the following ten guidelines would improve accessibility to more than half of the sites tested at low cost and with a very low barrier to implementation. Many of the points simply allude to good html coding others are more specific to improving accessibility:

1 Provide alternative short text for all non-text elements (such as images), if one is unable to write a short description, then use a longer piece of text rather than nothing.

2 Use relative positioning, rather than absolute so that different types of browser for different needs can cope.

3 The content of the site must be fully accessible without the need to use a mouse (the rendering of content should not depend on JavaScript event handlers/modal windows or other mouse-driven events.

4 Use the <label> tag to define the form of different elements, or least a minimum use the title attribute.

5 The text of references has to be intelligible beyond its context in the page.

6 The primary language must be defined in the <html> tag using the lang attribute.

7 A web site should provide summaries for tables using the summary attribute within the <table> tag.

8 Separating characters must be used between hyperlinks.

9 The <title> tag must identify the subject of the web page correctly.

10 All html should be validated and html tags closed correctly, so that assistive technologies can parse the content accurately without manual intervention or correction.

Sunday, February 13, 2011

IPv4 and IPv6

As you may have heard there is no more space on the Internet. The addresses available to websites and other internet locations under IPv4 will run out very soon, which potentially means no more new websites. Yippee! But, is IPv4 the IPocalypse or the Y2K of 2011?
The Internet operates by transferring data in small packets that are independently routed across networks as specified by an international communications protocol known as the Internet Protocol. Each data packet contains two numeric addresses that are the packet’s origin and destination devices. Since 1981, IPv4 has been the publicly used Internet Protocol, and it is currently the foundation for most Internet communications.
Internet Protocol version 6 (IPv6) is a version of the Internet Protocol (IP) that is designed to succeed Internet Protocol version 4 (IPv4). The Internet’s growth has created a need for more addresses than IPv4 has. IPv6 allows for vastly more numerical addresses, but switching from IPv4 to IPv6 may be a difficult process.
IPv4 allows approximately four billion addresses (it’s a 32-bit system so actually there are 4,294,967,296 many of which are private and reserved, like the 192.168.1.1 type addresses used locally by network equipment and computers). IPv6 is 128-bit and so allows 2 to the power of 128, that’s 340 undecillion, which is plenty go round if we can make the leap.
There are lots of organisations “squatting” on unused blocks of IP addresses, and Stanford actually released some of its IPs to free up addresses. So, if more of those could be released it would stave off the IPocalypse for a few more months.
The problem is that IPv6 does not play nicely with IPv4, it effectively is a parallel, independent network and exchanging traffic between the two requires special gateways. In December 2010, despite marking its 12th anniversary as a Standards Track protocol, IPv6 was only in its infancy in terms of general worldwide deployment; Google reported that penetration was less than one percent of Internet-enabled hosts in any country in 2008. Thankfully, IPv6 has now been implemented on all major operating systems in use in commercial, business, and home consumer environments and firmware for domestic routers should be available with relative ease.
So, what’s the problem? Why don’t we simply make the leap from IPv4 to IPv6?
Bottom line is money.
On 8 June, 2011, Google, Facebook, Yahoo!, Akamai and Limelight Networks will be first to carry out an IPv6 24-hour “test flight“, which is meant to motivate organizations across the industry – Internet service providers, hardware makers, operating system vendors and web companies – to prepare their services for IPv6 to ensure a successful transition as IPv4 addresses run out. Whether this persuades anyone to do the necessary will depend on budgets, profit margins and whoever wants to untie the purse strings first.