JSFiddle - React, Tailwind, and code Playground
HTML
<form name="myForm" action="http://upload.wikimedia.org/wikipedia/commons/3/30/Googlelogo.png" onsubmit="return Validate()" method="get">
<input type="checkbox" name="live" value="yesno">You are alive.
<br>
<input type="checkbox" name="type" value="person">You are a person.
<br>
<input type="checkbox" name="eyes" value="color">Your eyes have color.
<br>
<input type="submit" value="Submit">
</form>
JavaScript
function Validate() {
var checkboxes = processCheckboxes();
if (checkboxes.all.length == checkboxes.checked.length) {
alert("All are checked");
} else if (checkboxes.checked.length > 0) {
alert("Some checked");
} else {
alert("None checked");
}
return false;
}
function processCheckboxes() {
var checkboxes = document.querySelectorAll('input[type=checkbox]');
var checked = [].filter.call( checkboxes, function( el ) {
return el.checked
});
return { all: checkboxes, checked: checked };
}