Removal of the showModalDialog API

Question

With the impending removal of the showModalDialog API from various browsers, our company like many others who provide large scale enterprise web applications are now faced with a significant dilemma.

Whilst we have centralised the calls to showModalDialog down to 3 lines of code, we extensively rely on this code to provide feedback from modal user prompts (a quick search of the solution reveals around 2400 instances).

We could rip out showModalDialog fairly easily and replace it with a Javascript/css based alternative, that's not a problem. The issue we face is that all of the calling code will no longer be blocking e.g.

if(doConfirm(...)) {
   ...
} else {
   ...
} 

The above will simply fall through due to the introduction of a non-blocking alternative. We also cannot use the in-built blocking methods (alert, confirm) as the dialog buttons are customised in many cases and are also styled to fit in with our application.

Based on the above, are there any pragmatic workarounds/solutions that could be employed to avoid having to re-factor so much legacy previously blocking code?

Answer 1

You can avoid using callback functions by using my showModalDialog polyfill, which pauses execution of subsequent statements until the modal is closed. It does so by using generators, promises and the yield keyword. It works in the newest Opera and Google Chrome.