textarea文本域實時顯示輸入的字符長度

直接上代碼，沒什麼說的

定義的div

	  <div>
        <textarea name="content" class="layui-textarea" id="area" maxlength="50"
          placeholder="輸入5-50個字符" onkeyup="javascript:texLength(this, 50, 'textarea_length');"
          style="height: 100px;width: 81%;"></textarea>
        <span class="red" id="textarea_length">0</span> / <span class="num_count">50</span>
      </div>

function方法

    function texLength(obj, maxlength, id) {
      var curr = obj.value.length;
      if (curr > maxlength) {
        layer.msg('字數在' + maxlength + '字以內');
      } else {
        document.getElementById(id).innerHTML = curr;
      }
    }