<select id="user_id">
<option value="1">Пункт 1</option>
<option value="2">Пункт 2</option>
<option value="3">Пункт 3</option>
</select>
<input id="inp">
<input type="button" value="choose"
onclick = "
a = document.getElementById('user_id');
b = document.getElementById('inp');
for (i=1; i<a.options.length; i++) {
if (a.options[i].innerHTML == b.value) {a.options[i].selected = true; return}
}
"> |