Consume data from XML file in an HTML5 application?
You can do that by using Ajax and a Javascript XML parser. The best way to do that is with a JS library, like jQuery.
Check out jQuery ajax to grab your XML: http://api.jquery.com/jQuery.ajax/
jParse is a pretty decent xml parser: http://jparse.kylerush.net/
Ajax is for accessing pages in the same domain. If you need to grab a file on a different domain you'll have to find a different solution.