js强制限制输入允许两位小数

　　　　　　<input type="text" value="@item.CostCash.Value.ToString("#0.00")" class="cost" onKeyUp="amount(this)"  onBlur="overFormat(this)" />    

　　　　　　/**
         * 实时动态强制更改用户录入
         * arg1 inputObject
         **/
        function amount(th) {
            var regStrs = [
                [‘^0(\\d+)$‘, ‘$1‘], //禁止录入整数部分两位以上，但首位为0
                [‘[^\\d\\.]+$‘, ‘‘], //禁止录入任何非数字和点
                [‘\\.(\\d?)\\.+‘, ‘.$1‘], //禁止录入两个以上的点
                [‘^(\\d+\\.\\d{2}).+‘, ‘$1‘] //禁止录入小数点后两位以上
            ];
            for (var i = 0; i < regStrs.length; i++) {
                var reg = new RegExp(regStrs[i][0]);
                th.value = th.value.replace(reg, regStrs[i][1]);
            }
        }
        /**
         * 录入完成后，输入模式失去焦点后对录入进行判断并强制更改，并对小数点进行0补全
         * arg1 inputObject
         **/
        function overFormat(th) {
            var v = th.value;
            if (v === ‘‘) {
                v = ‘0.00‘;
            } else if (v === ‘0‘) {
                v = ‘0.00‘;
            } else if (v === ‘0.‘) {
                v = ‘0.00‘;
            } else if (/^0+\d+\.?\d*.*$/.test(v)) {
                v = v.replace(/^0+(\d+\.?\d*).*$/, ‘$1‘);
                v = inp.getRightPriceFormat(v).val;
            } else if (/^0\.\d$/.test(v)) {
                v = v + ‘0‘;
            } else if (!/^\d+\.\d{2}$/.test(v)) {
                if (/^\d+\.\d{2}.+/.test(v)) {
                    v = v.replace(/^(\d+\.\d{2}).*$/, ‘$1‘);
                } else if (/^\d+$/.test(v)) {
                    v = v + ‘.00‘;
                } else if (/^\d+\.$/.test(v)) {
                    v = v + ‘00‘;
                } else if (/^\d+\.\d$/.test(v)) {
                    v = v + ‘0‘;
                } else if (/^[^\d]+\d+\.?\d*$/.test(v)) {
                    v = v.replace(/^[^\d]+(\d+\.?\d*)$/, ‘$1‘);
                } else if (/\d+/.test(v)) {
                    v = v.replace(/^[^\d]*(\d+\.?\d*).*$/, ‘$1‘);
                    ty = false;
                } else if (/^0+\d+\.?\d*$/.test(v)) {
                    v = v.replace(/^0+(\d+\.?\d*)$/, ‘$1‘);
                    ty = false;
                } else {
                    v = ‘0.00‘;
                }
            }
            th.value = v;
        }