Internal Server Error

/www/wwwroot/shinatian/view/home/moon_qu.html:71
    69|         
月出时间：<%=think.datetime(moonrise,'YYYY-MM-DD HH:mm:ss')%>
    70|         
月落时间：<%=think.datetime(moonset,'YYYY-MM-DD HH:mm:ss')%>
 >> 71|         
月照时长：<%=controller.picTime((moonset.getTime()-moonrise.getTime())/1000)%>
    72|         

    73|           经度：东经
    74|           <%=jingwei.lon%>（<%=controller.toDegrees(jingwei.lon)%>）

Cannot read property 'getTime' of undefined