To catch exceptions in JavaScript, use try…catch…finally. JavaScript implements the try...catch...finally construct as well as the throw operator to handle exceptions.
You can catch programmer-generated and runtime exceptions, but you cannot catch JavaScript syntax errors.
Example
You can try to run the following code to learn how to catch exceptions in JavaScript −
<html>
<head>
<script>
<!--
function myFunc() {
var a = 100;
try {
alert("Value of variable a is : " + a );
}
catch ( e ) {
alert("Error: " + e.description );
}
finally {
alert("Finally block will always execute!" );
}
}
//-->
</script>
</head>
<body>
<p>Click the following to see the result:</p>
<form>
<input type = "button" value = "Click Me" onclick = "myFunc();" />
</form>
</body>
</html>