How to set up a checkbox to activate when a number less than a certain value is entered

[L Gryfe]

I am creating a form that will post the results for certain test results on a building. Users will insert particular numbers (e.g., concentration of certain gases, etc.). If number meets acceptable standards (e.g., below acceptable maximum), then I would like a check box to turn on that says the building meets the safety standards. 

let A = air quality value

let B = maximum accepted value

let C = checkbox indicating pass

So, if A < B, then C is ON (pass); if A > B, C is OFF (fail)

[try67]

You can use the calculation event of a (hidden) text field to do it.

For example:

this.getField("C").checkThisBox(0, Number(this.getField("A").valueAsString)<Number(this.getField("B").valueAsString));

Please be very careful, though, as many PDF viewers will not execute this code and you could get false results, which in this case can even be dangerous!

[L Gryfe]

Thanks for the input. Not sure I want to use a solution that isn't 100% reliable, though, since this form will be out "in the wild" where I can't control who's using it or where it's being distributed.

[try67]

Then I recommend you don't use any automatic calculations. Let the users fill in everything themselves and be responsible for the outcome.