Shouldn't really happen, but if it does, can't really argue that point 
Main troubles that I come across are ...
- ElementID must be unique in the page as a whole.
- I try to assign ElementID to everything on the Delphi side where feasible. I don't much like the autoassigned versions and run into trouble with that approach when using other JS libraries.
- In pure JS/HTML, creating elements dynamically usually means creating them and using appendChild to move them about. In Delphi, the same logic applies but it is implemented by assigning certain properties.
I might have a look at your code, maybe tomorrow, as I'm curious what you're up to here. I did write up something that might be related awhile back, not the dynamic part but the multi-form part, if you've not run across it in your travels already. Form management to speedup app - #9 by AndrewSimard