How to update a Project Task's property say 'PercentComplete'?

Hi Everyone,

I am new to the Microsoft-Sharepoint platform, so apologies if I sound stupid.

Could you please let me know if there is a way to UPDATE properties within a ProjectServer object like a 'Task' property say 'Finish' or effectively update 'PercentComplete' using Javascript or through the browser?

I can access the property using below GET call:

URL:

https://<PPM_SERVER_NAME>/sites/pwa/_api/ProjectServer/Projects('800ff3cb-99bf-e111-9f1e-00155d022681')/Tasks('850ff3cb-99bf-e111-9f1e-00155d022681')/PercentComplete

Request:

<d:PercentComplete m:type="Edm.Int32">0</d:PercentComplete>

I would like to update the above property OR any other property to make above says '50%', using any kind of POST call within the browser or Javascript engine/jQuery/Ajax, etc.

Any pointers would really be appreciated.

Thanks,

Pramod