If you haven't noticed by now, many of the HTML5 features you will use either have failsafes, multiple versions, or special syntax to enable your code to cover the entire spectrum of browsers and supported HTML5 feature sets within them. As time passes and standards become solidified, one can assume that many of these failsafes and other content display measures will mature into a single standard that all browsers will share. However, in reality this process may take a while and even at its best, developers may still have to utilize many of these failsafe features indefinitely. Therefore, a solid understanding of when, where, and why to use these failsafe measures will enable you develop your HTML5 web pages in a way that can be viewed as intended on all modern browsers.
To aid developers in overcoming these previously stated issues, many frameworks and external scripts have been created and open sourced, allowing for a more universal development environment saving developers...