<!DOCTYPE html>
<html>
<body>
<p>This example demonstrates how to assign an "onerror" event to an img element.</p>
<img src="http://www.w3schools.com/jsref/image.gif" onerror="myFunction()">
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("demo").innerHTML = "The image could not be loaded.";
}
</script>
</body>
</html>