HTML
DOCTYPE is required to enable standards mode for HTML documents. e.g.
<!DOCTYPE html>
Hypertext Markup Language 5
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML //EN”
“http://www.japrox.com/TR/html4/strict.dtd”>
Audio and Video are not part of the HTML4 specification.
Audio and Videos are integral parts of HTML5 specifications e.g. <audio> and <video> tags
Vector Graphics is possible with the help of technologies such as VML, Silverlight, Flash, etc.
Vector graphics are an integral part of HTML5 e.g. SVG and canvas.
It is almost impossible to get the true GeoLocation of a user browsing any website especially if it comes to mobile devices.
JS GeoLocation API in HTML5 helps identify the location of the user browsing any website (provided the user allows it)
Browser cache can be used as temporary storage.
Application Cache, Web SQL database, and Web storage are available as client-side storage. Accessible using JavaScript interface in HTML5 compliant browsers.
Web Sockets are not available. Generally, used mechanisms are long polling and streaming.
Full duplex communication channels can be established with servers using Web Sockets. Accessible using JavaScript interface in HTML5 compliant browsers.
Works with all old browsers.
Most modern browsers have started supporting HTML5 specifications e.g. Firefox, Mozilla, Opera, Chrome, Safari, etc.
Does not allow JavaScript to run in the browser. JS runs in the same thread as the browser interface.
Allows JavaScript to run in the background. This is possible due to JS Web worker API in HTML5.
