在JavaScript中实现统计文本框Textarea字数

哈哈，编的很巧妙呀，学习了！！！！

http://www.williamlong.info/archives/1830.html

<script language="javascript">  
function countChar(textareaName,spanName)
{  
 document.getElementById(spanName).innerHTML = 140 - document.getElementById(textareaName).value.length;
}  
</script>  
可以输入<span id="counter">140</span>字<br/>
<textarea id="status"  name="status" rows="6" cols="40" onkeydown='countChar("status","counter");' onkeyup='countChar("status","counter");'></textarea>