JQ 数字验证

 $.fn.extend({
        checknum: function (min, max, accurate) {
            if ($(this).val() != "") {
                $(this).val(parseFloat($(this).val()).toFixed(accurate))
            }
            else {
                $(this).val(parseFloat('0').toFixed(accurate))
            }
            $(this).bind('keyup', function () {
                event = window.event || event;
                if (event.keyCode == 37 || event.keyCode == 39) {
                    return;
                }
                var thisinput = $(this);
                var st = '';
                for (var i = 0; i < accurate; i++) {
                    st += '\\d';
                }
                st = '^(\\-)*(\\d+)\\.(' + st + ').*$';
                if (accurate == 0) {
                    reg1 = /[^-\d]/g
                }
                else {
                    reg1 = /[^-\d.]/g
                }
                var reg = new RegExp(st)
                if (thisinput.val().indexOf('-') > 0)
                {
                    thisinput.val(thisinput.val().replace("-", ""));
                }
                thisinput.val(thisinput.val().replace(reg1, "").
                replace(".", "$#$").replace(/\./g, "").replace("$#$", ".")
                   .replace("-", "$#$").replace(/\-/g, "").replace("$#$", "-")
                    .replace(reg, '$1$2.$3'));
                if (thisinput.val() > max) {
                    if (thisinput.val().indexOf('.') == -1) {
                        var val = '' + max;
                        thisinput.val(thisinput.val().substring(0, val.length - 1))
                    }
                    else {
                        thisinput.val(max.toFixed(accurate));
                    }
                }
                if (thisinput.val() < min) {
                    thisinput.val(min.toFixed(accurate));
                }
            });
            $(this).blur(function () {
                if ($(this).val() == "") {
                    var tempval = 0;
                    tempval = tempval.toFixed(accurate);
                    $(this).val(tempval);
                }
                else {
                    $(this).val(parseFloat($(this).val()).toFixed(accurate));
                }
            });
            $(this).focus(function () {
                var tempval = 0;
                tempval = tempval.toFixed(accurate);
                if ($(this).val() == tempval || $(this).val() == '' || $(this).val() == '0') {
                    $(this).val("");
                }
            });
        }
    });