Attach (recommended) or Link to PDF file here:
[multiple.pdf](https://github.com/mozilla/pdf.js/files/6344777/multiple.pdf)

Steps to reproduce the problem:
1. Write something in a field

What is the expected behavior? (add screenshot)
The 3 fields must have the same value

What went wrong? (add screenshot)
The 2 other fields are empty

The three fields share the same name `Text3`.
It works as expected in Adobe and Chrome.
optionElement.textContent = option.displayValue;
      optionElement.value = option.exportValue;
      if (this.data.fieldValue.includes(option.exportValue)) {
        optionElement.setAttribute("selected", true);
      }
      selectElement.appendChild(optionElement);
    }
    const getValue = (event, isExport) => {
      const name = isExport ? "value" : "textContent";
      const options = event.target.options;
      if (!event.target.multiple) {
        return options.selectedIndex === -1
          ? null
          : options[options.selectedIndex][name];
      }
      return Array.prototype.filter
        .call(options, option => option.selected)
        .map(option => option[name]);
    };
    const getItems = event => {
      const options = event.target.options;
      return Array.prototype.map.call(options, option => {
        return { displayValue: option.textContent, exportValue: option.value };
      });
    };
    if (this.enableScripting && this.hasJSActions) {
      selectElement.addEventListener("updatefromsandbox", event => {
        const { detail } = event;
        const actions = {
          value() {