Internet appears everywhere in our life. Form as a data gathering component is the must have component in a web app. When the page is submitting data to the server, if it takes a relative long time for the backend server to process the data, then the client users will feel lost while waiting for this if he cannot get any indication about what's happening. They may even reclick the button which will cause the data resubmission. This affects the user experience and also the system performance and stability.