Hi,
I am in the process of designing my first web page and am confused about making it compatible with all the different web browsers. Can you please help?
Thanks
How does this work with older versions of browsers? If your site validates what is the oldest version of each of the main browsers that you can you assume it will work correctly in? Also how do you check each of the different versions of browsers?
Cross-browser compatibility is pretty easy to do, just as long as you’re coding a website
yourself. If you’re starting in Wordpress or Blogger, it’s almost impossible to validate in
W3C. Just so you know, you don’t have to be validated, to have sites look the same in all
browsers… but if you are validated, they usually will. 
As mentioned, the best way to ensure cross browser compatiblity is to validate with W3C Validator. That will make your layout more universal as far as how it is displayed in all browser types. Always make sure as you are coding the layout to frequently be checking to make sure it is valid or you will run into alot of problems trying to locate the error after it is all complete. Keep testing in different browsers also to make sure everything looks as it should.
If you use either an XHTML or HTML doctype and validate your html on the w3c validator your web page should display correctly in the latest and recent versions of IE, Firefox (the 2 biggies), Opera, Safari and Chrome.
Apart from Internet Explorer, there is relatively little need to check older versions. Pretty much everyone using Safari, Chrome or Opera will be running the latest version. The majority of Firefox users will at least be running a very recent version, although remember that Win2k and older don’t support v3 so it may be worth checking in v2.
If you write it properly, you won’t have to worry much about differences between browsers - current browsers are very good about adhering to standards, at least for basic HTML and CSS.
By ‘properly’, I mean using strict HTML rather than deprecated elements with a full doctype, and making sure you have valid code (Kalon has given a link to the validator, an essential tool), you should find that all modern browsers behave in pretty much the same way.
There’s no substitute for installing IE, Firefox, Chrome, Safari and Opera and testing in all five of them. If you do that and find any bugs that only affect some browsers and not others, come back and ask about them then!
Most modern browsers (FF, Opera, Chrome) can be downloaded and use next to eachother. For IE there are different options. You can use the IE Tester which can be downloaded here: IE Tester which gives you all IE versions all the way back to IE5 or you can set up a virtual IE environment
Quick and dirty and simplistic: there’s IE6 and there’s everything else. Code it in HTML 4.01 Strict, test it in whatever non-IE browser you like until it works the way you want it, validates, etc. Then open it in IE6 and prepare to be dismayed.