textarea输入框限制字数

<textarea onkeyup="checkLen(this)"></textarea>

<div>您还可以输入 <span id="count">200</span> 个文字</div>

<script type="text/javascript">

function checkLen(obj) {

var maxChars = 200;//最多字符数

if (obj.value.length > maxChars)  obj.value = obj.value.substring(0,maxChars);

var curr = maxChars - obj.value.length;

document.getElementByIdx_x("count").innerHTML = curr.toString();

}

</script>