Merge pull request #6 from rexsunces/master

index.js中的绝对路径改为相对路径
Merge pull request #7 from rexsunces/master

换回绝对路径，使github.io上的示例能工作
返回按钮url fix
Merge pull request #5 from HADB/master

Merge pull request #6 from rexsunces/master