The latest versions of JavaScript added exception-handling capabilities. 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.
Here is the try...catch...finally block syntax −
<script> <!-- try { // Code to run [break;] } catch ( e ) { // Code to run if an exception occurs [break;] } [ finally { // Code that is always executed regardless of // an exception occurring }] //--> </script>
Example
You can try to run the following code to implement try…catch…finally statement 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>