jsp取不到输入的值
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>管理员登陆</title><link href="images/login.css" rel="stylesheet" type="text/css" /></head><script language="javascript">function check(){ if(login.UserName.value==""){ alert("请输入账户名"); return false; history.back(); login.UserName.focus(); } else { alert(login.UserName.value); } if(login.Password.value==""){ alert("请输入密码"); return false; history.back(); login.Password.focus(); } }</script><body><div id="wrap"> <div id="header"> </div> <div id="content-wrap"> <div class="space"> </div> <form name="login" action="" method="post"> <div class="content"> <div class="field"><label>账 户:</label><input class="username" name="adminname" id="UserName" type="text" /></div> <div class="field"><label>密 码:</label><input class="password" name="adminpw" id="Password" type="password"/><br/></div> <div class="btn"><input name="submit" type="submit" class="login-btn" value="" onClick="return check()"/></div> </div> </form> </div> <div id="footer"> </div></div> </body></html>