如何用PHP或JS控制：标题限制为4-20个汉字，内容10-3000个汉字呢？此文本大致如下：谢谢！
<html>
<head>
</head>
<body>
<form method='POST' action='fbjypx_yjzlb.php?action=login'>
<table border="0" align="center" width="750" cellspacing="0" cellpadding="0">
<tr>
<td width="100%" class="f2">密 码：<input type="text" name="mm" size="20" onMouseOver = "this.style.backgroundColor = '#E5F0FF'" onMouseOut = "this.style.backgroundColor = ''">
</td>
</tr>
<tr>
<td width="100%" class="f2">标 题：<input type="text" name="bt" size="40" onMouseOver = "this.style.backgroundColor = '#E5F0FF'" onMouseOut = "this.style.backgroundColor = ''">
<font class="f1">（23个汉字以内）</font></td>
</tr>
<br>
<tr>
<td width="100%" class="f2">内 容：<font class="f1">（3000个汉字以内）</font></td>
</tr>
<tr>
<td width="100%" >
<textarea rows="20" name="nr" cols="105" onMouseOver = "this.style.backgroundColor = '#E5F0FF'" onMouseOut = "this.style.backgroundColor = ''"></textarea></td>
</tr>
<tr>
<td width="100%" >
<input type="submit" value="提 交"> <input type="reset" value="重 来"></td>
</tr>
</table>
</form>
</body>
</html>
