I have the following script which works, but has one annoying issue:
I would use an onload handler to call the chart functions. It should wait for the page to load, then add the chart.
$(function(){
google.load("visualization", "1", {packages:["corechart"]});
google.setOnLoadCallback(drawChartAjax);
});
If this doesn't work, perhaps you could add a load handler to the footer div.