I have the following script which works, but has one annoying issue:
You can also take advantage of Google Chart events to listen for when the chart has loaded and perform an action. It may require you to initially hide the chart container or overlay a loading icon. Example:
google.visualization.events.addListener(chart, 'ready', function() {
// Do something like ...
/* $('#chart_div').css('visibility', 'visible'); // provided this was already hidden
$('.loading-icon').hide(); // if it exists in your HTML */
});