I will give my suggestion, without having to create <script>
but putting right into the <select>
OBS: I put the first option of <select>
as "Select", because if already enter a <option>
that has link, even selecting it, vc will not be directed to the page. So I put a "placehoder
" at first.
See how it looked in the example
select option[data-default] {
color: #999; /* cor simulando que o campo está desabilitado depois que abre o select */
}
<select name="forma" onchange="location = this.value;">
<option selected data-default>- Selecione -</option>
<option value="/">StackOverflow</option>
<option value="https://google.com/">Google</option>
<option value="pagina-1.php">Página 1</option>
<option value="pagina-2.html">Página 1</option>
</select>