Change

Can I use a javascript if/else function to change the select options of a form? I don't want to use CSS to hide/display different dropdown menus, so here is what I've ccome up with:

<script>
function getType() {
var x = document.getElementById("food").value;
var items;

if (x === "fruit") {
items = "Apple" || items = "Oranges" || items = "Bananas";
else {
items = "Eggplants" || items = "Olives"
}
document.getElementById("pickone").value;
}

<input type="text" id="food">

 <select id="pickone">
   <option id="1"></option>
   <option id="2"></option>
 </select>

I can't seem to find any documentation about how to do this, so any help would be great.