jsp动态换背景问题
有个index.html文件里面有4张图我想点一张图,test.jsp页面的背景就换一下 
 我用 
 String   p=request.getParameter( "user "); 
 String   s=user.substring(25); 
 获得了图片的相对路径   
 但是怎么用这个变量s换背景呢?我的jsp刚刚学,所以我用的是js的 
 document.body.background方法,但是发现document.body.background=s根本不行   
 好像是jsp根js变量不能混用   
 代码: 
 ============================================== 
 test.jsp     
  <%!   String   s;%>  
  <% 
 String   p=request.getParameter( "user "); 
 s=user.substring(25); 
 %>      
  <script   language= "javascript ">  
 document.body.background=s; 
  </script>  
 =========================================================   
 index.html   
  <script   language= "javascript ">  
 function   test(obj){ 
 	form1.user.value=obj.src;  	  	 
 	form1.submit();  	 
 } 
  </script>  
  </head>  
  <body>  
  <form   id= "form1 "   name= "form1 "   method= "post "   action= "Test.jsp ">  
  <input   name= "user "   type= "text ";   onclick= "alert( "aaa ") "   />    
  </form>  
  <a   href=#;>  <img   src= "image/banner.jpg "   alt= " "   width= "232 "   height= "166 "   border= "0 ";id= "img1 ";   onclick= "test(this) "/>  </a>  
  <a   href=#;>  <img   src= "image/login.gif "   alt= " "   width= "232 "   height= "166 "   border= "0 ";id= "img1 ";   onclick= "test(this) "/>  </a>  
  <a   href=#;>  <img   src= "image/rem.gif "   alt= " "   width= "232 "   height= "166 "   border= "0 ";id= "img1 ";   onclick= "test(this) "/>  </a>  
  <a   href=#;>  <img   src= "image/pic_foot.gif "   alt= " "   width= "232 "   height= "166 "   border= "0 ";id= "img1 ";   onclick= "test(this) "/>  </a>  
 ===================================================================== 
------解决方案-------------------- <script language= "javascript ">  
 document.body.background=s; 
  </script>    
 改为 
  <script language= "javascript ">  
 document.body.background= ' <%=s%>  '; 
  </script>
------解决方案--------------------ding