Onchange event on a selectbox with same text but different value

Question

Let's say I have this selectbox :

<select id="my-select">
  <option value="1">text_generated_dynamically</option>
  <option value="2">text_generated_dynamically</option>
</select>

As you can see, the text of each option is generated dynamically by another function.

I'm using JS onchange event on the selectbox to launch a function and it works fine.

For example :

document.getElementById("my-select").onchange = function(){
    alert(document.getElementById("my-select").value)
};

But sometimes, the dynamically generated options return the same text and the onchange event doesn't detect the change anymore since it's the same text value.

How can I listen to the VALUE instead of TEXT so the event knows there is a change even if the text is the same on both options ?