<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>标题页</title>
<script language="javascript">
function textcontrol(content)
{
if (txt.length > 200) // 如果文本框的长度大于200
document.txt.value=document.txt.value.substring(0, 200); //截取前200字符
}
</script>
</head>
<body>
<textarea name="txt" cols="50" rows="10" onPropertyChange="textcontrol(txt.value)">
</textarea>
</body>
</html>