jquery 限制textarea文本框输入字符数量代码

(function($) {
    $.fn.extend( {
        limiter: function(limit, elem) {
            $(this).on("keyup focus", function() {
                setCount(this, elem);
            });
            function setCount(src, elem) {
                var chars = src.value.length;
                if (chars > limit) {
                    src.value = src.value.substr(0, limit);
                    chars = limit;
                }
                elem.html( limit - chars );
            }
            setCount($(this)[0], elem);
        }
    });
})(jQuery);

//To setup the limiter, simply include a call similar to the one below:
var elem = $("#chars");
$("#text").limiter(100, elem);

<h3>设计理念说明（200字以内）</h3>
<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.getElementById("count").innerHTML = curr.toString();
}
</script>