I just discovered JqGrid and have been working extensively with it for the last few days and have found these forums to be an invaluable source of information, so I thought I would give something back.

The following code can be used to HTTP Auth protect your JSON/XML/ i/o script. 

First you must base64 encode the username:password like

var credentials = "<?php echo base64_encode("myusername:secretpassword");?> ";

In order to add the credentials into the request header you must implement the loadBeforeSendEvent in your jQGrid:

loadBeforeSend: function(xhr)

    {

     xhr.setRequestHeader("Authorization","Basic "+credentials);
     return xhr;

} 

And thats it! it will login with the provided credentials! I believe if you wish to use Digest auth you just replace Basic with Digest but I am not 100% on that....

Thanks jQGrid Team, keep up the good work and thanks for a great widget!

David