Ajax无刷新提交表单和显示

ajax无刷新表单提交：
<!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=gb2312" /> 
<title>Ajax留言本</title> 
<style type="text/css"> 
* { padding: 0; margin: 0; } 
li { list-style: none; } 
body { background: #f9f9f9; font-size: 14px; } 
#box { width: 450px; padding: 10px; border: 1px solid #ccc; background: #f4f4f4; margin: 10px auto; } 
#fill_in { margin-bottom: 10px; } 
#fill_in li { padding: 5px 0; } 
#fill_in .text { width: 380px; height: 30px; padding: 0 10px; border: 1px solid #ccc; line-height: 30px; font-size: 14px; 
font-family: arial; } 
#fill_in textarea { width: 380px; height: 100px; line-height: 20px; padding: 5px 10px; border: 1px solid #ccc; font-size: 
14px; font-family: arial; overflow: auto; vertical-align: top; } 
#fill_in .btn { border: none; width: 120px; height: 30px; border: 1px solid #ccc; background: #fff; color: #666; font-size: 
14px; position: relative; left: 42px; } 
#fill_in .ret { border: none; width: 120px; height: 30px; border: 1px solid #ccc; background: #fff; color: #666; font-size: 
14px; position: relative; left: 42px;margin-left:50px; } 
#message_text { display: none; } 
#message_text h2 { font-size: 14px; padding: 6px 0 4px 10px; background: #ddd; border-bottom: 1px solid #ccc; } 
#message_text li { background: #f9f9f9; border-bottom: 1px solid #ccc; color: #666; overflow: hidden; } 
#message_text h3 { padding: 10px; font-size: 14px; line-height: 24px; } 
#message_text p { padding: 0 10px 10px; text-indent: 28px; line-height: 20px; } 
</style> 
<script type="text/javascript"> 
var oBtn = null; 
var oForm = null; 
var oText = null; 
var oTextarea = null; 
var timer = null; 
var speed = 0; 
var oLi = null 
var oH3 = null; 
var oP = null; 
window.onload = function() 
{ 
oBtn = document.getElementById("btn"); 
oBtn.onclick = getValue; 
}; 
function getValue() 
{ 
document.getElementById("message_text").style.display = "block"; 
oForm = document.getElementsByTagName("form")[0]; 
oText = document.getElementById("text"); 
oTextarea = document.getElementsByTagName("textarea")[0]; 
oUl = document.getElementById("message_text").getElementsByTagName("ul")[0]; 
oForm.onsubmit = function(){ return false; }; 
if( oText.value == "" || oTextarea.value == "" ) 
{ 
alert("就二个框，你还不写全了啊？"); 
return; 
} 
oLi = document.createElement("li"); 
oH3 = document.createElement("h3"); 
oP = document.createElement("p"); 
oH3.innerHTML = oText.value; 
oP.innerHTML = oTextarea.value; 
if(oUl.childNodes[0]) 
{ 
oUl.insertBefore(oLi,oUl.childNodes[0]); 
} 
else 
{ 
oUl.appendChild(oLi); 
} 
oLi.appendChild(oH3); 
oLi.appendChild(oP); 
oText.value = ""; 
oTextarea.value = ""; 
var h = oLi.offsetHeight; 
oLi.style.height = '0px'; 
if(timer) 
{ 
clearInterval(timer); 
} 
timer = setInterval("goTime("+h+")", 35); 
goTime(h); 
} 
function goTime(target) 
{ 
var top = oLi.offsetHeight; 
speed += 3; 
top += speed; 
if(top > target) 
{ 
top = target; 
speed *= -0.7; 
} 
if(top===target && Math.abs(speed) < 3) 
{ 
clearInterval(timer); 
timer = null; 
oLi.style.height = target + "px"; 
} 
oLi.style.height = top + "px"; 
} 
</script> 
</head> 
<body> 
<div id="box"> 
        <h3>请留下您的足迹:</h3> 
    <div id="message_text"> 
        <h2>显示留言:</h2> 
        <ul></ul> 
    </div> 
    
    
    <ul id="fill_in"> 
        <form> 
            <li>姓名：<input id="text" type="text" class="text" /></li> 
            <li>内容：<textarea id="content" style="300px; height:100px"></textarea></li> 
            <li><input id="btn" type="submit" value="提交" class="btn" /><input id="ret" type="reset" value="重写" class="ret" /></li> 
        </form> 
    </ul> 
    

</div> 
</body> 
</html>
实例截图：