Users need feedback that their action is being performed but may take a while to complete
Provide a feedback page with animation
You are designing a site where slow back-end systems are connected to. Some requests to the back-end system may take 5 to 30 seconds to complete and the users need some feedback telling them that their request is being performed and that they'll have to wait a bit. Only use this pattern when it is not possible to speed up the back-end processing time. Typically, a Travel Site
using this when flight-availability is being looked-up. It also occurs frequently in a Web-based Application
Provide information about the reason for the slow response so that users can have understanding of the problem. Also add an animation or real progress feedback so that users get a sense of continuity or progress.
Although it would be best to provide real progress feedback, this is often not technically possible in a web environment. Providing this type of feedback is the least that should be done for users who need to wait.