JSFiddle - React, Tailwind, and code Playground
HTML
<br />Apples
<input type="checkbox" name="fruit" checked/>Oranges
<input type="checkbox" name="fruit" />Mango
<input type="checkbox" name="fruit" />
<br />Yes
<input type="radio" name="yesorno" id="yes" onClick="checkboxes();" />
JavaScript
function checkboxes()
{
var inputElems = document.getElementsByTagName("input"),
count = 0;
for (var i=0; i<inputElems.length; i++) {
if (inputElems[i].type == "checkbox" && inputElems[i].checked == true)
{
count++;
alert(count);
}
}}