CRM iFrame associated view record count MS Dynamics

I have a crmForm with an iFrame that displays an associeted Entity. I want to validate that the associated view in the iFrame has records when the user saves the parent crmform. Using javascript, how can I find the record count of the crmGrid in the 开发者_Go百科iFrame.

The closest I come is

var frameDoc = document.getElementById('IFrame_contacts').contentWindow.document;
var recordcount = frameDoc.all['crmGrid'].innergrid.Allrecords.lenght;

That just gives me an innergrid not found error.

Thanks Oliver

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You were close. You want var recordcount = frameDoc.getElementById("crmGrid").InnerGrid.SelectedRecords.length;