default select option as blank

Maybe this will be helpful

<select>
    <option disabled selected value> -- select an option -- </option>
    <option>Option 1</option>
    <option>Option 2</option>
    <option>Option 3</option>
</select>

-- select an option -- Will be displayed by default. But if you choose an option, you will not be able to select it back.

You can also hide it using by adding an empty option

<option style="display:none">

so it won’t show up in the list anymore.

Option 2

If you don’t want to write CSS and expect the same behaviour of the solution above, just use:

<option hidden disabled selected value> -- select an option -- </option>