Fix #1: sink into dead loop when already at the top
Merge branch 'master' of github.com:sunaiwen/scroll2Top
update readme
Merge branch 'gh-pages'
update sample page
add test ,fix bugs
update .gitignore
clear files that pushing carelessly
fix bugs because of regardless of async feature
fix test bug
fix codes according to test
update .gitignore
Merge branch 'master' into gh-pages