Check whatsapp account.

[Badrinathjanghel]

Hi
I am badrinath janghel, i want to know that how to know any number has whatsapp account or not.

When we add new contact in contact manager after this it shows whatsapp icon in that perticular contact if this contact has whatsapp account.

so i want to know this is done how.
please response me for this.

Thanks in advance