window.onload doesn't work with Google Chart API

I want to put google chart into开发者_如何学C window.onload, but it doesn't show anything instead, in the status bar, it shows 'Transferring data from www.google.com...' I know if we put the code outside window.onload it will surely work, but I want to put in window.onload. Any suggestions? thanks

Here is my code

---

drawChart callback should be invoked when API would be loaded, for that you need to define callback key in third argument of google.load function:

(function(window, document, undefined) {
  window.onload = function() {
    google.load('visualization', '1', {
      packages:['corechart'],
      callback: drawChart
    });

    function drawChart() {
      console.log('drawChart');
    }
  };
})(window, window.document);