求高手解决关于img调用jsp，然后在jsp页面ajax提交的问题

a.jsp 中嵌入下面的jsdocument.write('<img style="width:0px;height:0px" src="http://172.20.15.81:8080/flow/collect.jsp"/>这是collect.jsp，a.jsp被访问后。打出了“*********”但ajax没有执行。直接调用collect.jsp却可以执行ajax。不知是何原因，求高手解决
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ include file="mc/common/common_mc_head.jsp" %>
<html>
<body>
<%
System.out.print("**********");
%>
<script type="text/javascript">
var url = "http://172.20.15.81:8080/flow/portal/interfaces!collect.action?id=${id}&tpages=${tpages}&ttimes=${ttimes}&tzone=${tzone}&tcolor=${tcolor}&sSize=${sSize}&referrer=${referrer}&vpage=${vpage}";
$.get(url);
</script>
</body></html>