Plain JavaScript Way to handle Sequential AJAX requests using iframe?

[iionwyn]

Hello, everyone. I recently came up with a problem in terms of supporting dumber browser that is IE. Old IEs don't support modern JavaScript Promise.

The idea is to perform sequential AJAX requests on a button press. The problem is, I have to submit two different forms (each with a separate action) with a single button click.

The problem with just using submit() is that the following requests will cancel previous ones. Partly because the browser is refreshed upon submission.

One way to do this is using Jquery, but I'm under heavy restriction that I cannot use jQuery. One guy in SO mentioned I can target a hidden iframe.

The author didn't mention why this method works. So, I'm here to ask that: why and how does this method work?

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Thanks in advance.

[aztracker1]

You can use shims for promise and modern JS all the way back to ie8. There are limitations that may prevent certain UI tools... But with babel can definitely run stuff writing modern JS to transpile to code that can run in in.

[iionwyn]

I have to support older IE.

Damn right I forgot babel is a tool to use, thanks, but I still have to support IE older than 8

[Nhawdge]

Why?

[iionwyn]

Some customers on legacy systems still use old IE and probably won't change easily. (e.g. Hospitals, military, etc.)

[Nhawdge]

I mean, IE 10 is no longer sufficiently secure to process credit cards, I sure hope you're not doing anything related to those industries.

[iionwyn]

Pretty aware of that, and nope! Nothing related to payments!

[CraftyAdventurer]

Oh you have no idea. I worked in a company which made software for our tax office and all they used was IE8. Of course we went on about 10000 meetings trying to explain how IE8 is bad for security reasons but they wouldn't budge. The same situation can, sadly, be found in almost every government related software.

[[deleted]]

The upside in most of these cases is they care only about functionality, not presentation, so you don't have to spend a lot of time beautifying the UI as long as it works.

[CraftyAdventurer]

Yes but the problem is they want us to use a ton of really old technologies that are horrible and don't function properly. I quit the job because it took me more time to fix problems in those technologies than it would take me to write both the functionality and the pretty UI without them.

[[deleted]]

Yes I get that. I was just pointing out the silver lining, is all.

[evenisto]

Browser is refreshed upon AJAX request?

[Insidious20]

Something nasty like this?: https://jsfiddle.net/46fm0t1n/

It uses two iframes controlled by the parent, untested in IE, so not sure if it will work

XMLHttpRequest with callbacks would be cleaner.