Need selection textframe width

Hi All,

simple Request:

If Selected textframe is "100mm" (alert pass)

Otherwise selected textframe is !=100mm (alert fail)

Code is below:

app.activeDocument.viewPreferences.horizontalMeasurementUnits = app.activeDocument.viewPreferences.verticalMeasurementUnits = MeasurementUnits.MILLIMETERS;

if(app.selection[0].geometricBounds[3] - app.selection[0].geometricBounds[1] == "100mm")

{

    alert("pass")

    }

else

{

    alert("fail")

    }

I dont know where I did mistake.

Could anyone give solution for my request.

Thanks in advance

Beginner_X