JScript is based on COM, setting the variable / call function is implemented by iDispatch. In .NET, the method in calling iDispatch is achieved by reflection, i.e., via system.type.invokememember. This method calls IDispatch :: getidsofNames and IDispatch :: Invoke to call the method and properties in the COM Automation object. reference
Binding for Office Automation Servers with Visual C # .NET
If there is the following HTML,
