<!DOCTYPE html>
<html lang="en">
<script>
let counter = 0;
function onLoad() {
setTimeout(swapFocus, 0);
}
function swapFocus() {
const id = 'button' + (1 + (counter++ & 1));
document.getElementById(id).focus();
if (counter === 4) {
console.log('quit');
} else {
setTimeout(swapFocus, 0);
}
}
function onFocus(id) {
console.log('onfocus ' + id);
}
function onBlur(id) {
console.log('onblur ' + id);
}
</script>
<body onload="onLoad()">
<div>
<button id="button1" class="button"
onfocus="onFocus('button1')" onblur="onBlur('button1')">
Button1
</button>
</div>
<div>
<button id="button2" class="button"
onfocus="onFocus('button2')" onblur="onBlur('button2')">
Button2
</button>
</div>
</body>
</html>