JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <form name="myForm">
        <select name="dayOfYear" id="sel_dayOfYear">
            <option value="">Choose...</option>        
        </select>
    </form>
</div>

CSS

#container {
    height: 40px;
    border: 1px solid red;
    overflow: auto;
}

JavaScript

var sel = document.forms['myForm']['dayOfYear'],
    i = 1;
for (i; i <= 365; i++) {
    var newOpt = document.createElement('option');
    newOpt.value = newOpt.innerHTML = i;
    sel.appendChild(newOpt);
}