Identify how Browsers and Platforms affect Display and Performance

Although Web pages are designed with particular fonts and colors, it does not mean the pages will be viewed with the same fonts or colors. Certain display options such as fonts, font size, and background color can be altered by users in the browser preference file. There are multiple cross-browser and cross-platform compatibility issues you should be aware of as you create Web pages, including:

When Microsoft Internet Explorer was the dominant browser and had 90% market share, there was nothing much to do but regard the browser as a "black box". Today we have open source browsers with more than half of the usage share and it is a good time to take look under the rendering engine's hood and see what is inside a web browser. There exists alot of C++ code. As a web developer, learning the internals of browser operations helps you make better decisions and know the justifications behind development best practices. We recommend you spend some time digging in; we guarantee you will be glad you did.

The main function of a browser is to present the web resource you choose, by requesting it from the server and displaying it in the browser window. The resource is usually an HTML document, but may also be a PDF, image, or some other type of content. The location of the resource is specified by the user using a URI (Uniform Resource Identifier). The way the browser interprets and displays HTML files is specified in the HTML and CSS specifications. These specifications are maintained by the W3C (World Wide Web Consortium) organization, which is the standards organization for the web. For years browsers conformed to only a part of the specifications and developed their own extensions. That caused serious compatibility issues for web authors and today most of the browsers more or less conform to the specifications. Browser user interfaces have a lot in common with each other. Among the common user interface elements are:

1. Address bar for inserting a URI
2. Back and forward buttons
3. Bookmarking options
4. Refresh and stop buttons for refreshing or stopping the loading of current documents
5. Home button that takes you to your home page

Strangely enough, the user interface of the browser is not specified in any formal specification, it just comes from good practices shaped over years of experience and by browsers imitating each other. The HTML5 specification does not define UI elements a browser must have, but lists some common elements. Among those are the address bar, status bar and tool bar. In addition, there are features unique to a specific browser, for example Firefox's downloads manager.

Whenever possible, consider providing alternatives. For example, allow users to select the browser plug-in appropriate for their platform.
This may involve additional HTML coding and/or converting a movie clip into different formats.

For a list of browser versions and their coding compatibilities, see

1. Mozilla.org,
2. nodejs.org, and
3. Ajaxian.

Click the link below to analyze differences between browsers.
Analyze Browser Differences