http://blog.csdn.net/junval/archive/2007/08/29/1763541.aspx
代码
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="TextArea.aspx.cs" Inherits="TextArea" %>
<!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 runat="server">
<title>textarea 无边框无滚动条自适应高度的实现</title>
<style type="text/css">...
.info {...}{
font-size: 12px;
overflow:hidden;
background-color: #ffffcc;
color: black;
width:100%;
line-height:12px;
padding-right:5px;
padding-left:5px;
font-family: courier;
width:100%;
letter-spacing:0;
border-style:none;
}
</style>
<script language="javascript" type="text/javascript">
function setRows(obj){
var textarea = obj;
var cols = textarea.cols;
var str = textarea.value;
str = str.replace(/ ?/, " ");
var lines = textarea.rows;
var chars = 0;
for (i = 0; i < str.length; i++) {
var c = str.charAt(i);
chars++;
if ( c == " ")
{
lines ++;
}
else
{
if (i > lines * (cols/2) ) //这里是中文模式除2 如果是输入英文字符修改为1 即可
{
lines ++;
}
}
}
textarea.setAttribute("rows", lines);
textarea.style.height = lines*12 + "px";
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<textarea id='LogC' onkeyup='setRows(this)' class='info' cols='75'rows='12'>可以根据内容自适应调整高度</textarea>
</div>
</form>
</body>
</html>