只能输入数字装X版

jquery.onlyNum.js：

(function ($) {
    $.fn.numeric = function (only_integer, precision) {
        var decimal = only_integer === false ? "." : "";
        var reg = new RegExp("[^0-9" + decimal + "]", "g");
        var precision = precision || 2;
        this.css("ime-mode", "disabled");
        this.keyup(function (e) {
            var key = e.which;
            if (key != 8 && key != 9 && key != 13 && key != 16 && key != 35 && key != 36 && key != 37 && key != 39 && key != 46) {
                var position = $(this).cursorPosition();
                var old_len = $(this).val().length;
                $(this).val($(this).val().replace(reg, ""));
                $(this).cursorPosition(position - (old_len - $(this).val().length))
            }
        });
        this.keydown(function(e) {
            var key = e.which;
            if (only_integer === false && key === 190) {
                if (this.value.indexOf(".") > -1) {
                    return false
                }
            }
        });
        this.blur(function () {
            if ($(this).hasClass("placeholder")) {
                return
            }
            if ($(this).val().length > 1) {
                var tmp = parseFloat($(this).val());
                tmp = isNaN(tmp) ? "" : tmp + "";
                if (only_integer === false) {
                    var index = tmp.indexOf(".");
                    if (index > -1) {
                        tmp = tmp.substring(0, index + precision + 1)
                    }
                }
                $(this).val(tmp)
            }
        });
        this.bind("dragover", function (e) {
            e.originalEvent.dataTransfer.dropEffect = "none";
            e.preventDefault();
            return false
        });
        return this
    };
    $.fn.cursorPosition = function (value) {
        var elem = this[0];
        if (elem && (elem.tagName == "TEXTAREA" || elem.type.toLowerCase() == "text")) {
            if (window.attachEvent) {
                var rng;
                if (elem.tagName == "TEXTAREA") {
                    rng = event.srcElement.createTextRange();
                    rng.moveToPoint(event.x, event.y)
                } else {
                    rng = document.selection.createRange()
                }
                if (value === undefined) {
                    rng.moveStart("character", -event.srcElement.value.length);
                    return rng.text.length
                } else {
                    if (typeof value === "number") {
                        var index = this.cursorPosition();
                        index > value ? (rng.moveEnd("character", value - index)) : (rng.moveStart("character", value - index));
                        rng.select()
                    }
                }
            } else {
                if (value === undefined) {
                    return elem.selectionStart
                } else {
                    if (typeof value === "number") {
                        elem.selectionEnd = value;
                        elem.selectionStart = value
                    }
                }
            }
        }
    }
})(jQuery);