Refresh iframe when widget opens

[Mirco]

Hi, I have a widget that contains an iframe, inside this iframe I have a table that contains some data. Depending on the status of some variables, when I open the widget, the content of the table inside the iframe must change. Now I don't want to set the refresh option of the iframe to 1 second, I only want that it will be refreshed only at the opening of the widget.
Do you have some ideas? 

Thanks!