JSFiddle - React, Tailwind, and code Playground

HTML

<form id="testForm">
    <select name="element1">
        <option value="">-</option>
        <option value="1">1</option>
    </select>
    <select name="element2">
        <option value="">-</option>
        <option value="1">1</option>
    </select>
    <input type="reset" value="Reset"/>
    <input type="submit" value="Submit"/>
</form>

JavaScript

$(function() {
    $("#testForm").on("submit", function() {
        $(this).find('select option:selected[value=""]').parent().attr("disabled", "disabled");
        alert("ok");  // for debug purposes
        return false; // this stops the form from actually being submitted
    });
    $("#testForm").on("reset", function() {
        $(this).find('select option:selected').parent().removeAttr("disabled");
    });
});