写一个JS函数 接收2个参数 a为textarea的id,b为span的id(显示)
Code
<script type="text/javascript">
function show(a,b) {
var maxl = 400
var s = document.getElementById(a).value.length + 1;
if (s > maxl)
document.getElementById(a).value = document.getElementById(a).value
.substr(0, maxl - 1)
else
document.getElementById(b).innerHTML = "已输入:" + s + "/" + maxl
+ " 字符"
}
</script>
<s:textarea onkeydown="show();" id="a"></s:textarea>
<div><span id ="b">已输入字符:</span></div>