In some cases you could get this kind of hexadecimal numbers from Sharepoint for the PermMask: 0xb008431061, or 0x1b03c4313ff, and so on. To verify the PermMask against the different level of permissions you can proceed with the below method (using functions from core.js): var permMask = ‘0x1b03c4313ff’; var permissions = new SP.BasePermissions(); permissions.initPropertiesFromJson({High:GetPermMaskH(permMask), Low:GetPermMaskL(permMask)}); // […]