title: TypeError: google.visualization is undefined
body: <p>I'm trying to work with Google charts API, but I get an error I can't understand:</p>
  
  <p>Here is my code:</p>
  
  <pre><code>&lt;script type="text/javascript" src="https://www.google.com/jsapi"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="js/statistics/overview.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>And the code from overview.js is like this:</p>
  
  <pre><code>var statisticsOverview = {
      init: function() {
          google.load("visualization", "1", {packages: ["corechart"]});
          google.setOnLoadCallback(this.drawIncomeChart());
          google.setOnLoadCallback(this.drawExpensesChart());
          google.setOnLoadCallback(this.drawEconomiesChart());
      },
      drawIncomeChart: function() {
          var data = [
              ['Year', 'Income'],
              ['October 2013', 1000],
              ['January 2014', 1170],
              ['March 2014', 660]
          ];
          var options = {
              title: 'Income Performance',
              colors: ['green']
          };
          var id = 'chart_income';
  
          this.drawLineChart(data, options, id);
      },
      drawExpensesChart: function() {
          var data = [
              ['Year', 'Expense'],
              ['October 2013', 1000],
              ['January 2014', 1170],
              ['March 2014', 660]
          ];
          var options = {
              title: 'Expense Performance',
              colors: ['red']
          };
          var id = 'chart_expenses';
          this.drawLineChart(data, options, id);
      },
      drawEconomiesChart: function() {
          var data = [
              ['Year', 'Savings'],
              ['2004', 1000],
              ['2005', 1170],
              ['2006', 660],
              ['2007', 1030]
          ];
  
          var options = {
              title: 'Savings Performance',
              colors: ['orange']
          };
  
          var id = 'chart_economies';
          this.drawLineChart(data, options, id);
      },
      drawLineChart: function(data, options, id) {
          console.log(google.visualization);
          var chartData = google.visualization.arrayToDataTable(data);
  
          var chart = new google.visualization.LineChart(document.getElementById(id));
          chart.draw(chartData, options);
      }
  };
  
  statisticsOverview.init();
  </code></pre>
  
  <p>This is strange, because console.log() will give me the google object with the property visualization. What am I doing wrong?</p>