按钮点击后无法在下一个文本框输入信息都输入在上面的,哪个大哥帮忙看下!
<!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>用户登录</title>
<script>
function ad(str)
{
    document.form1.p1.value = document.form1.p1.value + str;
}
</script>
<style>
/* CSS Document */
body{
margin-left: 0px;
margin-top: 0px;
margin-right: 0px;
margin-bottom: 0px;
   }

h1, h2, h3, h4, h5, h6, p {
margin-top:0px;
padding-right:0px;
padding-left:0px;
}
#center{margin-left:auto; margin-right:auto}
ul,li{
list-style:none outside none;
margin:0;
padding:0;
}
#all{ width:1080px; height:750px; margin:0 auto; border:#003399 solid 1px; background:url(image/loginimg/4.jpg) no-repeat;} 
.in  input{ width:218px; height:28px; line-height:28px; display:block; font-size:26px; background:#FFFFFF; border:#006666 1px solid; padding-left:5px; color:#0066FF;}
.info{background:url(image/loginimg/pics.jpg) no-repeat;}
.in{ width:451px; margin:0 auto; margin-top:220px;}.in .haoma{ width:451px; height:46px; margin-bottom:20px;}
.in .haoma li{ float:left;  }
.in .haoma .k1{padding-top:6px; }
.in .haoma .k2{padding-top:10px; height:28px; line-height:28px; color:#006633; font-weight:bold;padding-left:66px;display:inline; }
.in .anniu{ height:55px;  width:451px; text-align:center;}
.in .anniu li{ height:39px; width:65px; float:right; text-align:center; line-height:39px;display:block;  margin:9px;_margin:4px 0 0 2px;margin-right:15px;}
.in .anniu img{ border:none;}
   .in .anniu li a{ color:#3399CC; font:"Verdana"; font-size:23px; font-weight:bolder; text-decoration:none; display:block; }
   .in .anniu li a:active{ height:39px; display:block; color:#F00; }
   .in .anniu image/loginimg{ border:none; }
 
.in .xia{ height:52px;  width:451px; text-align:center;background:url(image/loginimg/111.jpg) no-repeat;}
.in .xia img{ border:none;}
   .in .xia li{  display:inline;  margin:10px; width:45px; height:52px;color:#009999; }
   .in .xia a{ color:#336633; font-weight:bold;}
   .in .xia image/loginimg{ border:none; margin-top:5px;}
   
   .in .tool{ height:32px; width:228px; margin-left:12px;}
   .in .tool li{ float:left; display:inline; width:57px; text-align:center;}
   .in .tool image/loginimg{ border:none; cursor:pointer; }
   .in .tool a{ display:block; height:32px; width:57px; cursor:pointer;}
   .in .tool a:hover{ display:block;}
   
.in .top{ overflow:hidden; display:block; height:100px;}
  .in .top image/loginimg{ display:block; overflow:hidden;}
.in .buttom{ overflow:hidden; display:block; height:93px; color:#3399CC; color:#FFFFFF}
   in .buttom image/loginimg{ display:block; overflow:hidden;}
.left{ float:left;}
.rigth{ float:left;}
</style>
</head>
<body>
   <div id="all">     
    <div class="in">
           <ul class="haoma">
           <li class="k2">
           户号:&nbsp;
           </li>
             <li class="k1">
            <form method=post action="" name="form1"><input name="p1" type="text" /></form></li>
                <li></li>
      </ul>
       <ul class="haoma">
           <li class="k2">
           密码:&nbsp;
           </li>
             <li class="k1">
            <form method=post action="" name="form2"><input name="p1" type="password" /></form></li>
                <li></li>
      </ul>
       <div class="info">
<ul class="anniu">
          <li><a href="javascript:ad('5')"><image/loginimg src="image/loginimg/5.png" /></a></li>
          <li><a href="javascript:ad('4')"><image/loginimg src="image/loginimg/4.png" /></a></li>
          <li><a href="javascript:ad('3')"><image/loginimg src="image/loginimg/3.png" /></a></li>
          <li><a href="javascript:ad('2')"><image/loginimg src="image/loginimg/2.png" /></a></li>
          <li><a href="javascript:ad('1')"><image/loginimg src="image/loginimg/11.png" /></a></li>
       </ul>
       
<ul class="anniu">
          <li><a href="javascript:ad('0')"><image/loginimg src="image/loginimg/0.png" /></a></li>
          <li><a href="javascript:ad('6')"><image/loginimg src="image/loginimg/6.png" /></a></li>
          <li><a href="javascript:ad('7')"><image/loginimg src="image/loginimg/7.png" /></a></li>
          <li><a href="javascript:ad('8')"><image/loginimg src="image/loginimg/8.png" /></a></li>
          <li><a href="javascript:ad('9')"><image/loginimg src="image/loginimg/9.png" /></a></li>
       </ul>
       
<ul class="xia">
       <li><a href="index.html"><image/loginimg src="image/loginimg/button1.png" /></a></li>
          <li><a href="#" id="backbutton"><image/loginimg src="image/loginimg/button2.png" /></a></li>
          <li><a href="#" id="rows"><image/loginimg src="image/loginimg/button3.png" /></a></li>
          <li><a href="yongdian/user.htm"><image/loginimg src="image/loginimg/button4.png" /></a></li>
       </ul>
       </div>
     </div>
   
</div>     <script type="text/javascript">
   (function(){
    var back = document.getElementById('backbutton');
    back.onclick=function(){
        var numbers = document.form1.p1.value;
var len=numbers.length;
        document.form1.p1.value=numbers.slice(0,len-1);
return false;
      }
   })();
   
   (function(){
    var back = document.getElementById('rows');
    back.onclick=function(){
        var numbers = document.form1.p1.value;
var len=numbers.length;
        document.form1.p1.value=numbers.slice(0,len-100);
return false;
      }
   })();
   </script></body>
</html>