1. 只能输入数字

    <script type="text/javascript">

        $(function() {

            $("#<%=txtNetOrderNo.ClientID %>").keypress(function(e) {

                return e.keyCode >= 46 && e.keyCode <= 57;

            });

        });

    </script>

 

2. 输入文本框时显示剩余字数

HTML:

<div>

JS:

<script type="text/javascript">

        //返回val的字节长度

        function getByteLen(val) {

            var len = 0;

            for (var i = 0; i < val.length; i++) {

                if (val[i].match(/[^\x00-\xff]/ig) != null) //全角

                    len += 2;

                else

                    len += 1;

            }

            return len;

        }

        //返回val在规定字节长度max内的值

        function getByteVal(val, max) {

            var returnValue = '';

            var byteValLen = 0;

            for (var i = 0; i < val.length; i++) {

                if (val[i].match(/[^\x00-\xff]/ig) != null)

                    byteValLen += 2;

                else

                    byteValLen += 1;

                if (byteValLen > max)

                    break;

                returnValue += val[i];

            }

            return returnValue;

        }

        $(function() {

            var _area = $('textarea#txtPrizeNote');

            var _info = _area.next();

            var _max = _area.attr('maxlength');

            var _val;

            _area.bind('keyup change', function() { //绑定keyup和change事件

                if (_info.find('span').size() < 1) {//避免每次弹起都会插入一条提示信息

                    _info.append(_max);

                }

                _val = $(this).val();

                _cur = getByteLen(_val);

                if (_cur == 0) {//当默认值长度为0时,可输入数为默认maxlength值

                    _info.text(_max);

                } else if (_cur < _max) {//当默认值小于限制数时,可输入数为max-cur

                    _info.text(_max - _cur);

                } else {//当默认值大于等于限制数时

                    _info.text(0);

                    $(this).val(getByteVal(_val,_max)); //截取指定字节长度内的值

                }

            });

        });

    </script>