How to Set default content type and change the order of document library content type using ecma script.

Hello,

Please suggest on below points

1) How to Set default content type in document library using ecma script or sharepoint web service?

2) How to change order of content type using ecma script or web service?

3)How to hide content type on interface using ecma or webservice?

Thanks in Advance.

Nilesh Jain