anchor.diff:  
   <script type="text/javascript">
   //声明Pic对象
  +var count = 0;
   var id;
   var name;
   var size = 0;
  
positive.code: 	}
  	
  	function judge(){
  		var count = <%=session.getAttribute("coursesNum")%>;
  		//var testimg = "images/test.jpg";
  		//document.getElementById("myCanvas").style.backgroundImage="url("+urlpic+")";
  		if ( count == 1 ){//当天有一节课，返回SUCCESS
  
negative.code: 			  Object temp1 = session.getAttribute("coursesInfo");
  			  course = (ArrayList<CourseInfo>) temp1;
  			  String cname = course.get(0).getCname();
  			  url = (String)session.getAttribute("classPicUrl");%>
  			
  			document.getElementById("courseTeancher").innerHTML= str;
  			var bgurl = '"url('+<%=url%>+')"';
  			if(bgurl==null){
  				document.getElementById("bgurl").innerHTML="还未开始点名或者图片上传不成功，请耐心等候";
  				}else{
  