How to login to salesforce through URL ?

As normal user, we access Salesforce.com from web browser https://login.salesforce.com to access production instance or https://test.salesforce.com to access sandbox instance (if you have any).

But, some organisations need to access Salesforce directly from another application (and not implemented SSO), we can add username and password include as login parameters to direct login to Salesforce, here we go:

https://www.salesforce.com/login.jsp?un=user@email.com&pw=secret

The same applied for sandbox:

https://test.salesforce.com/login.jsp?un=user@email.com&pw=secret