how to grab <xf:submission> element in DOM using JavaScript

Hi,

I know we could get the DOM object for a instance in the model using JavaScript code, like..

var oModel = document.getElementById("someModelId");
var oInstance = oInstance.getInstanceDocument("someInstanceId");

Is is it possible to do the same for a <xf:submission> element and how using JavaScript?

I have tried "oModel.getInstanceDocument('someSubmissionId')", "oModel.getElementById('someSubmissionId') and even "oModel.getElementByTagName('xf:submission')", none of them seemed to be working..

Thanks alot..

Yu yu