4.3 How is WEBEVENT Different?
The WEBEVENT function is not coded like a procedural LANSA function. The key differences include:
- WEBEVENT functions automatically terminate immediately after sending the page to the user, that is, immediately after a REQUEST or DISPLAY statement.
- WEBEVENT functions are designed with their processing logic first. The last operation must be the REQUEST or DISPLAY. The logic of the RDML function must be written specifically for this style of function.
- WEBEVENT functions cannot use any of the standard function keys, i.e. Exit, Cancel, Add, Change, Delete, Prompt, etc. because the function terminates once the display executes.
- WEBEVENT functions control user navigation using the USER_KEYS parameter of the DISPLAY or REQUEST command or by using links from one page to another. For details, refer to 4.7 WEBEVENT Routing.
- The LANSA function terminates after the REQUEST or DISPLAY so the transaction server is not required to maintain state. (Note: the transaction server is still used to process LANSA Web function jobs). The user is able to use the browser's Back button if they wish.
- The exchange of data between WEBEVENT functions is automatically handled by LANSA.
- WEBEVENT functions are not procedural. You must call your WEBEVENT functions directly using the PROCFUN keyword. These functions cannot be executed from a process menu.
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