Code refactoring.
Add int() helper instead of parseInt.

parseInt is a good option for string-int conversion,
but none for float-int conversion because of performance issue.

This is also to make the code clean.
More code refactoring.

It's never enough.
Remove IE6 specific fixes.

Just don't use IE6.
IE Pointer Events

Added support for PointerEvents (and MSPointerEvents) to support touch
in IE10 and 11.

Modified by @noraesae.