Jqplot 不显示图形绘图，没有 jquery 错误

我试图实现这个示例http://www.jqplot.com/examples/date-axes.php#chart2

这是我的代码

$script="var line1=[['2008-06-30 8:00AM',4], ['2008-7-14 8:00AM',6.5], ['2008-7-28 8:00AM',5.7], ['2008-8-11 8:00AM',9], ['2008-8-25 8:00AM',8.2]];";
            $script .= "$.jqplot('chart_periodi', [line1]";$script .= ", {
                legend:{show:true},
                title:'Aperture/ora nel tempo, da inizio a fine ciclo newsletter',
                axes:{
                    xaxis:{
      renderer:$.jqplot.DateAxisRenderer, 
      tickOptions:{formatString:'%b %#d, %#I %p'},
      min:'June 16, 2008 8:00AM', 
      tickInterval:'2 weeks'
    }
                },
                series:[{lineWidth:4, markerOptions:{style:'square'}}]
                highlighter: {sizeAdjust: 7.5},
                grid: {background:'#f3f3f3', gridLineColor:'#accf9b'},
                })";
            echo $script;
            $objResponse->script($script);

echo显示了这一点

var line1=[['2008-06-30 8:00AM',4], ['2008-7-14 8:00AM',6.5], ['2008-7-28 8:00AM',5.7], ['2008-8-11 8:00AM',9], ['2008-8-25 8:00AM',8.2]];$.jqplot('chart_periodi', [line1], {
                legend:{show:true},
                title:'Aperture/ora nel tempo, da inizio a fine ciclo newsletter',
                axes:{
                    xaxis:{
      renderer:$.jqplot.DateAxisRenderer, 
      tickOptions:{formatString:'%b %#d, %#I %p'},
      min:'June 16, 2008 8:00AM', 
      tickInterval:'2 weeks'
    }
                },
                series:[{lineWidth:4, markerOptions:{style:'square'}}]
                highlighter: {sizeAdjust: 7.5},
                grid: {background:'#f3f3f3', gridLineColor:'#accf9b'},
                })

我不明白问题出在哪里。我没有错误，但没有可见的情节。谢谢