One of the greatest problems with CSS, or Cascading Style Sheets, is the issue of cross browser compatibility. What may look great in Mozilla browsers looks terrible in Internet Explorer, and may totally break in Netscape. The biggest mistake a web designer or developer using CSS can make is to design for only one browser, or to assume that since the largest group of viewers use IE, to disregard its flaws that are apparent in other browsers.
Cross Browser Issues: CSS Hacks, Understanding Compatibility - Know More Browsers, and Differences (Page 3 of 5 )
Netscape 6 and up
Internet Explorer 5 and up
There was such a huge improvement in CSS support for Internet Explorer when Microsoft updated IE3 to IE4 that to date, it is still the largest browser upgrade for IE. Still, newer versions of IE have several issues, many of which were solved in version 6 for Windows and 5.5 for Mac. But because IE 5 is still one of the most popular versions of a web browser available, much consideration must be made for it with regards to CSS 2.1, even if it can behave oddly regarding your CSS.
However, even IE6 for Windows is buggy when it comes to margins of floated elements: it doubles them. There are other bugs like duplicate text in multiple floats, oversized content boxes, and several others. While there is no way we could cover every possible bug or fix in these two articles, we’ll look a an explanation as to what makes browsers different with regards to CSS compatibility, and a few fixes out there.
Why are they so different?
The answer to this question goes back to CSS not having standards adopted by all the browser vendors. If you know anything about CSS, you probably know a little of the history concerning it. What’s important to understand that Internet Explorer is used by almost 70% of people, the number of people using non-Microsoft browsers is only about 30%, even though that number is rising. It seems that Internet Explorer is the one with the most problems in the newer of the browsers with regards to compatibility. Being able to have your site look the same across all the browsers takes a bit of practice and skill.
The biggest problem with IE is that it tries to assume what to do, instead of following your CSS instructions step by step, as well as not supporting many of the CSS 2.1 standards that Netscape and Mozilla browsers do. W3Schools.com has a pretty good chart that shows which browsers support certain CSS commands, and which browsers do not. It will also list which version of CSS that browser supports. However, the chart only lists a few browsers, like IE, Firefox, and Netscape, but this is based upon the assumption that all other browsers are derived in some form or another from these browsers.