<!DOCTYPE html>
<html lang="en-US">
<body>
<p>Select some characters in the Input Field</p>
<input type="email" value="John Doe">
<script>
var x = document.getElementsByTagName("input")[0];
function myFunction() {
alert("Some text is selected");
}
x.addEventListener("select", myFunction);
</script> </body>
</html>