onerror Event

Fires when an error occurs during object loading.

Syntax

Inline HTML	<ELEMENT onerror = "handler" ... >	All platforms
Event property	object.onerror = handler	JScript (compatible with ECMA 262 language specification) only
Named script	<SCRIPT FOR = object EVENT = onerror>	Internet Explorer only

Event Handler Parameters

When this event is bound to the window object, the following parameters apply. These parameters are required in Microsoft® Visual Basic® Scripting Edition (VBScript).

Parameter	Description
sMsg	Optional. Description of the error that occurred.
sUrl	Optional. URL of the page on which the error occurred.
sLine	Optional. Line number on which the error occurred.

Remarks

Bubbles	No
Cancels	Yes
To invoke	Cause one of the following errors to occur: Run-time script error, such as an invalid object reference or security violation. Error while downloading an object, such as an image.
Default action	Displays the browser error message when a problem occurs. Executes any error handling routine associated with the event.

To suppress the default Internet Explorer error message for the window event, set the returnValue property of the event object to true or simply return true in JScript®.

The onerror event fires for run-time errors, but not for compilation errors. In addition, error dialog boxes raised by script debuggers are not suppressed by returning true. To turn off script debuggers, disable script debugging in Internet Explorer by clicking Tools, Internet Options, and then Advanced.

Event Object Properties

Although event handlers in the DHTML Object Model do not receive parameters directly, the handler can query the event object for data.

Event Object Properties

returnValue	Sets or retrieves the return value from the event.
srcElement	Retrieves the object that fired the event.
type	Retrieves the event name from the event object.

Example

The following examples use the onerror event to handle run-time script errors and object load errors.

Sample Code

This example specifies an invalid script entry. The script in the text field is evaluated when the Throw Error button is clicked. The onerror event fires because the script is invalid. The error results are inserted at the bottom of the sample page instead of in a dialog box.

<SCRIPT>
window.onerror=fnErrorTrap;
function fnErrorTrap(sMsg,sUrl,sLine){
   oErrorLog.innerHTML="<b>An error was thrown and caught.</b><p>";
   oErrorLog.innerHTML+="Error: " + sMsg + "<br>";
   oErrorLog.innerHTML+="Line: " + sLine + "<br>";
   oErrorLog.innerHTML+="URL: " + sUrl + "<br>";
   return false;
}
function fnThrow(){
   eval(oErrorCode.value);
}
</SCRIPT>
<INPUT TYPE="text" ID=oErrorCode VALUE="someObject.someProperty=true;">
<INPUT TYPE="button" VALUE="Throw Error" onclick="fnThrow()">
<P>
<DIV ID="oErrorLog">
</DIV>

This feature requires Internet Explorer 4.0 or later. Click the icon below to install the latest version. Then reload this page to view the sample.

This example shows how to set the handler for the onerror event in script before an image source is specified. When the invalid source is set on the IMG element, the event fires.

<SCRIPT>
var sImg='<IMG STYLE="display: none;" ID=oStub ALT="Default Text">';
function fnLoadFirst(){
   oContainer.innerHTML=sImg;
   oStub.onerror=fnLoadFail1;
   oStub.src="";
   oStub.style.display="block";
}
function fnLoadFail1(){
   oStub.alt="Image failed to load.";
   return true;
}
</SCRIPT>

<INPUT TYPE=button VALUE="Load First Image" onclick="fnLoadFirst()">
<DIV ID=oContainer></DIV>

This feature requires Internet Explorer 4.0 or later. Click the icon below to install the latest version. Then reload this page to view the sample.

Applies To

[ Object Name ] Platform Version Win16: Win32: Mac: Unix: WinCE: Version data is listed when the mouse hovers over a link, or the link has focus.	IMG, OBJECT, STYLE, window

See Also

onerrorupdate