Different Browsers

Your Web browser is a translation device. It takes a document written in the HTML language and translates it into a formatted Web page. The result of this translation is a little like giving two human translators a sentence written in French and asking them to translate it into English. Both will get the meaning across, but may not use the same words to do so.

The basic rules for translating HTML documents are established by the World Wide Web consortium, which publishes the official HTML standards. But there's considerable room for interpretation within those ground rules.
For example, the HTML standards say that the TABLE tag should support a CELLSPACING attribute to define the space between parts of the table. But standards don't define the default value for that attribute, so unless you explicitly define CELLSPACING when building your page, two browsers may use different amounts of white space in your table.

In addition, the HTML standards usually run ahead of what the browsers support. No browser as yet supports 100% of the HTML Version 5 standard, but some browsers come closer than others. Over the past few years Internet Explorer has done a much better job of this than Netscape Navigator, though Opera has done arguably the best job.

But since support for the latest HTML tags isn't universal, you could be building your pages with parts of the language that not all browsers understand. In that case the browser will ignore that part of your page it can't translate, and the way your page displays will be affected.

This problem is further complicated by browser-specific "HTML extensions." Back during the heyday of the Browser Wars, both Netscape and Microsoft tried to get a competitive edge by running ahead of the HTML standards, inventing their own tags and attributes.

The theory was that Web designers would fall in love with these attributes and put little buttons at the bottom of the page saying, "Best viewed with Netscape Navigator." So Internet users would rush to download that browser and, voila, Netscape would win the Browser Wars.

In practice no Internet user will download a new browser just to view your Web site, so these HTML extensions only created headaches for Web designers.

The best way to minimize these problems is to pay attention to browser compatibility when building your Web page. Avoid using HTML extensions and be careful about using cutting-edge features of the language that may not yet be supported by all the major browsers.

We also recommend you test your pages with HTML Toolbox and review its Browser Compatibility report.