<!DOCTYPE html>
<html>
<body>
<p>When you enter the input field, a function is triggered which sets the background color to yellow. When you leave the input field, a function is triggered which sets the background color to red.</p>
Enter your name: <input type="text" id="myInput" onfocusin="focusFunction()" onfocusout="blurFunction()">
<p><strong>Note:</strong> Firefox does not support the focusin and focusout events.</p>
<script>
// Focus = Changes the background color of input to yellow
function focusFunction() {
document.getElementById("myInput").style.background = "yellow";
}
// No focus = Changes the background color of input to red
function blurFunction() {
document.getElementById("myInput").style.background = "red";
}
</script>
</body>
</html>