js监听鼠标事件控制textarea输入字符串的个数

<table><tr><td width="150">短信内容：</td><td><textarea name="message" cols="96" rows="5" onKeyDown="textCounter(message,remLen,65);"onKeyUp="textCounter(message,remLen,65);"></textarea><td></tr><tr><td></td><td>您还可以输入:<input name="remLen" type="text" value="65" size="5" readonly="readonly">个字符,每条短信最大允许输入<strong>65</strong>个字符</td></tr></table>

<script>function textCounter(field, countfield, maxlimit) {if (field.value.length > maxlimit)field.value = field.value.substring(0, maxlimit);elsecountfield.value = maxlimit - field.value.length;}</script>