<style type="text/css">
*{
background-image:url("../image/4.jpg");
background-repeat:no-repeat;
background-size:100%,100%;
}
</style>
<body>
<div align="center" style="position: relative;top:200px">
<input type="button" value="管理员登录"onclick="javascrtpt:location.href='http://localhost:8080/18033212/admin/a_denglu.jsp'">
<input type="button" value="学生登录"onclick="javascrtpt:location.href='http://localhost:8080/18033212/student/s_denglu.jsp'">
<input type="button" value="教师登录"onclick="javascrtpt:location.href='http://localhost:8080/18033212/teacher/t_denglu.jsp'">
</div>
</body>