Add a sample based on text content
Add feature to suport ie.

For ie browser, the `.ps-container` element will add extra class `ie`
and `ie<version>`, like `ie6`, `ie7`, `ie8`, etc.
Add hover handlers for ie6.

Use scripts to add '.hover' class on the `.ps-container` and both
scrollbars when then mouse is over them because :hover is not supported
except 'a' element.
Fixed the scrollbar height for xp sp3 ie6

set 'font-size:0' for the scrollbar
Separate the function updating the css of scrollbars.
Fix ie6 scrollbar position problem.

This patch is in fact contributed by the idea of @maoziliang.