动态添加<option>元素来选择标签会破坏其功能

document.getElementById('metodode')
  .addEventListener('mousedown', function(e) {

    //keep track of the currently selected option
    const currentValue = this.value;

    this.innerHTML = '';
    const elemento = document.createElement('option');
    elemento.text = 'Escolha uma opçao';
    elemento.value = '';
    elemento.disabled = true;
    elemento.selected = true;
    this.appendChild(elemento);

    for (let i = 0; i < 5; i++) {
      const elemento = document.createElement('option');
      elemento.text = "test123-" + i;
      elemento.value = i;
      this.appendChild(elemento);
    }

    //restore the previously selected option (if it exists)
    //I'm using a general approach just to fit with
    //further scenarios beyond this simple demo
    const options = [...this.options];
    const matchingOption =
      options.find(opt => opt.value === currentValue);
    if (matchingOption) {
      matchingOption.selected = true;
    }
  
});

<select id="metodode" style="cursor:pointer;">
  <option id="first" value="" disabled selected>
    Escolha uma opçao
  </option>
</select>