JSFiddle - React, Tailwind, and code Playground

HTML

<p>
    <label><input name="fruit" type="radio" value="apple" /> Apple</label><br />
    <label><input name="fruit" type="radio" value="cherry" /> Cherry</label>
</p>

<p>
    <button id="my_btn">Which Fruit?</button>
</p>

JavaScript

function checkFruit(){
    var fruit_radio_pointers = document.getElementsByName("fruit");
    var which_fruit = null;
    for(var i=0; i<fruit_radio_pointers.length; i++){
        if(fruit_radio_pointers[i].checked){
            which_fruit = fruit_radio_pointers[i].value;  
            break;            
        }    
    }
    alert(which_fruit);
}
        
document.getElementById("my_btn").addEventListener("click", checkFruit, false);