cross browser testing of design
Everyone has their favorite browsers, and among web developers and graphic designers the loyalties over which is best can be as strong as religious and political beliefs.
But favoritism aside, the market share is strongly divided across the array of browsers, and the bulk of users out there are using Microsoft's Internet Explorer. To compound factors even further, the majority of IE users have version 8.0, despite the fact the Microsoft released its latest, version 9.0 over a year ago.
Internet Explorer has long been a thorn in the side of most web developers because of its lack of compliance to WC3 standards (World Wide Web Consortium). Version 7.0 and 8.0, both of which are still widely used today, had different interpretations of CSS (Cascading Style Sheets) standards than other browsers which caused them to display pages differently with often ugly results on the screen. They have done a great deal of work in bringing IE 9.0 into compliance with CSS 3 standards, but users of IE have only adopted it at a rate of only about 20%. Since version 9 is so drastically different from its predecessors, I am going to count it as a different browser all-together.
IE 8 and earlier make up nearly 40% of the browsers on desktops today, Followed by Google Chrome, Firefox, Safari, and then IE 9. This means that graphic features from CSS 3, such as rounded corners and shadows will not display in a huge portion of the available browsers, and padding and margins between elements on the page will differ also. You want to build to impress, but at the same time you don't want to alienate part of your potetial audience either.
A good web design needs to look good on all platforms. This doesn't mean you need to stay clear of the newer and more eloquent features of CSS3 in your site's layout and design, but you do need to pay attention to how a page will display that doesn't support the CSS3 enhancements.