JSFiddle - React, Tailwind, and code Playground

HTML

<form onsubmit="test()" action="POST">
    <label for="textbox-1">Textbox: </label>
    <input type="text" id="textbox-1" />
    <label for="checkbox-1">Checkbox: </label>
    <input type="checkbox" id="checkbox-1"/>
    <input type="submit"/>
</form>

JavaScript

function test(){
    event.preventDefault();
    var textbox1 = document.getElementById('textbox-1').value;
    var checkbox1 = document.getElementById('checkbox-1').checked;
    alert("Textbox value: " + textbox1 + " || checkbox: " + checkbox1);
    
}