how can i call a crmskript without login

I have a crmscript which give back an JSON.

I need to call my function.

When i call with blogic.fcgi in a private browser i come to the login mask

When i call with customer.fcgi?action=doscript in a private browser, that open the customer center but not my json

Is there another way to do that or it's my action bad ?

Thanks for your help