Debug.msTraceAsyncCallbackStarting Function

Associates the callback stack with a previously specified asynchronous operation.



Required. The ID associated with the asynchronous operation.

Call this function in the callback function for the asynchronous operation after the call to Debug.msTraceAsyncOperationCompleted.

Note Note

Some debugging tools, such as F12 developer tools, do not display the information sent to the debugger. Visual Studio supports this function and shows relevant information in the call stack.

asyncOperationId must correspond to the operation name previously returned from Debug.msTraceAsyncOperationStarting.

The following code provides an example of tracing an asynchronous call for a Windows Store app.

function asyncWrapperFunction() {
    var opID = Debug.msTraceAsyncOperationStarting('async trace');
    doSomethingAsync().then(function (result) {
        Debug.msTraceAsyncOperationCompleted(opID, Debug.MS_ASYNC_OP_STATUS_SUCCESS);
        // Process result of async operation.
    }, function (error) {
        Debug.msTraceAsyncOperationCompleted(opID, Debug.MS_ASYNC_OP_STATUS_ERROR);


function doSomethingAsync() {


Supported in the Internet Explorer 11 standards document mode. Also supported in Store apps (Windows 8.1 and Windows Phone 8.1). See Version Information. Not supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards. Not supported in Windows 8.

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