This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.


This is a proprietary Microsoft Internet Explorer alternative to the standard EventTarget.addEventListener() method.


attached = target.attachEvent(eventNameWithOn, callback)
The DOM element to listen for the event on
The name of the event to listen for, prefixed with "on", as if it were an event handler attribute. For example, you would use "onclick" to listen for the click event.
Callback function to call when the event is triggered on this target. The function will be called with no arguments, and with the this reference set to the window object.
Boolean indicating whether the event handler was successfully attached.


Not part of any specification.

Microsoft has a description on MSDN.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support No support No support 6 thru 10 [1] ? No support
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support No support No support ? ? No support

[1]: attachEvent() is no longer supported in IE11+. EventTarget.addEventListener() is supported in IE9+.

See also

Document Tags and Contributors

Contributors to this page: cvrebert, rolfedh
Last updated by: cvrebert,