JavaScript: The Definitive Guide, Fourth Edition

Name

Window.onerror — the handler invoked when a JavaScript error occurs

Availability

JavaScript 1.1; buggy in Netscape 6/6.1

Synopsis

You register an onerror event handler like this:

                  window.onerror=handler-func

The browser invokes the handler like this:

                  window.onerror(message, url, line)

Arguments

message

A string that specifies the error message for the error that occurred.

url

A string that specifies the URL of the document in which the error occurred.

line

A number that specifies the line number at which the error occurred.

Returns

true if the handler has handled the error and JavaScript should take no further action; false if JavaScript should post the default error message dialog box for this error.

Description

The onerror property of the Window object specifies an error handler function that is invoked when a JavaScript error occurs in code executing in that window. By default, JavaScript displays an error dialog box when an error occurs. You can customize error handling by providing your own onerror event handler.

You define an onerror event handler for a window by setting the onerror property of a Window object to an appropriate function. Note that unlike other event handlers in JavaScript, the onerror handler cannot be defined in an HTML tag.

When the onerror handler is invoked, it is passed three arguments: a string specifying the error message, a string specifying the URL of the document in which the error occurred, and a number that specifies the line number at which ...