indexOf() : Find first occurrence of a value in a string in JavaScript

JS Script:

<html>
<body>
<script type="text/javascript">
var str="Pritesh Taral";
document.write(str.indexOf("r") + "<br />");
document.write(str.indexOf("TARAL") + "<br />");
document.write(str.indexOf("Taral"));
</script>
</body>
</html>

Output in Browser :

1
-1
8