onerror Event

Fires when an error occurs during object loading.

dhtml语法

Inline HTML	<ELEMENT onerror = "handler" ... >	All platforms
Event property	object.onerror = handler	JScript only
	object.onerror = GetRef("handler")	Visual Basic Scripting Edition (VBScript) 5.0 or later only
Named script	<SCRIPT FOR = object EVENT = onerror>	Internet Explorer only

Event Information

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 and executes any error handling routine associated with the event.

Event Object Properties

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

available properties

altKey	Sets or retrieves a value that indicates the state of the ALT key.
altLeft	Sets or retrieves a value that indicates the state of the left ALT key.
ctrlLeft	Sets or retrieves the state of the left CTRL key.
returnValue	Sets or retrieves the return value from the event.
shiftLeft	Retrieves the state of the left SHIFT key.
srcElement	Sets or retrieves the object that fired the event.
type	Sets or retrieves the event name from the event object.

Remarks

To suppress the default Microsoft® Internet Explorer error message for the window event, set the returnvalue property of the event object to true or simply return true in microsoft 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 choosing internet options from the tools menu. click the advanced tab and select the appropriate check box(es).

Examples

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

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 Microsoft® Internet Explorer 4.0 or later. Click the following icon 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 Microsoft® Internet Explorer 4.0 or later. Click the following icon to install the latest version. Then reload this page to view the sample.

是否符合公共标准

There is no public standard that applies to this event.

Applies To

	IMG, OBJECT, STYLE, window

更多语法参考

onerrorupdate