Displaying only the drop-down options which are relevant

Question

Only those Drop Down Options which are relevant to me on a web-page should be visible to me. (Others should be hidden)

Example:

Instead of a drop-down which has options:

A B C D E F

I want only below 2 options to be visible to me A C

This would save our time and less chances of selecting incorrect option since the drop-down currently has more than 10 options and only 3 options are relevant to my team.

Kindly Note: We are not allowed to change the source code of the page, so I am hoping this is possible via scripts(JS) which can be run on Grease/Tamper Monkey.

Answer 1

For example you can disable all select-options except the relevant:

var opt = document.getElementById("yourSelectBoxId").getElementsByTagName("option");
for (var i = 0; i < opt.length; i++) {
  if(! ['A','C'].includes(opt[i].value)) {
    //disable it:
    opt[i].disabled = true;
    //or remove it:
    //opt[i].parentNode.removeChild(opt[i]);
  }
}