JSFiddle - React, Tailwind, and code Playground

HTML

<select name="opt" onchange="getval(this)">
    <option value="Select" selected disabled>Select</option>
    <option value="op1">Option 1</option>
    <option value="op2">Option 2</option>
</select>

JavaScript

function getval(sel) {
    if (sel.value == "op1") {
        alert("Option 1 Selected");
    } else if (sel.value == "op2") {
        alert("Option 2 Selected");
    }
    else
    {
        alert("EXCEPTION !");
    }
}