Verification of the same selected values in different selectors

[courtlanda]

This form interface is available:

in this particular example, each selects different meanings.

We've got to run the checks for the same selected values in different parts, like here:

This is where the "Presidium" is chosen in Part One and Part Two, which is a mistake in the form logic.

How is this verification on the same selected values in different select's forms to be applied to JavaScript?

[inna]

Elementary - you get the selected elements from both selters and compare, for example, at the time of the element selection in any of the selters.

var select1 = /* document.querySelector... */ ;
var select2 = /* ... */ ;
var selected1 = Array.from(select1).filter(e => e.selected);

var selected2 = Array.from(select2).filter(e => e.selected);
for (let el1 of selected1) {

for (let el2 of selected2) {

if (el1.text == el2.text) { /* do some... */ }
/* или так */

if (el1.value == el2.value) { /* do some... */ }

}

}