JSFiddle - React, Tailwind, and code Playground
HTML
<select id="selectVendor">
<option value="55" selected="selected">Company A</option>
<option value="56">Company B</option>
<option value="57">Company XYZCYK</option>
</select>
JavaScript
jQuery(function(){
var randRange = $('#selectVendor option').size();
var getThis = randomFromTo(0,randRange);
alert( $('#selectVendor option').eq( getThis ).attr('value') );
});
function randomFromTo(from, to){
return Math.floor(Math.random() * (to - from + 1) + from);
}