js 实现textarea剩余字数统计

针对textarea剩余字数统计
<div class="fankui-textarea">
    <span>留言：</span> <span class="wordwrap fr">你还可以输入<var class="word">500</var>个字</span>
    <textarea name="content" placeholder="此处限定500字"></textarea>
</div>
<script>
/*textarea还剩余字数统计*/
$(function () {
    var wordCount = $('.fankui-textarea');
    var textArea = wordCount.find('textarea');
    var  word = wordCount.find(".word");
    statInputNum(textArea, word);
});
function statInputNum(textArea, word) {
    var max = word.text();
    var curLength;
    textArea[0].setAttribute('maxlength', max);
    curLength = textArea.val().length;
    word.text(max-curLength);
    textArea.on('input propertychange', function () {
        var _value = $(this).val().replace(/\n/gi,"");
        word.text(max - _value.length);
    });
}
</script>