Plugin jQuery para criar máscaras para inputs

AddMask.js

(function ($) {
    var AddMask = {
        masks: {
            phone: function(value) {
                var new_value = '',
                    value = this.number(value);

                if (value.length <= 0) {
                    new_value = '';
                } else if (value.length < 3) {
                    new_value = '(' + value.substr(0, 2);
                } else if (value.length >= 3 && value.length <= 6) {
                    new_value = '(' + value.substr(0, 2) + ') ' + value.substr(2, 4);
                } else if (value.length >= 7 && value.length <= 10) {
                    new_value = '(' + value.substr(0, 2) + ') ' + value.substr(2, 4) + '-' + value.substr(6, 4);
                } else if (value.length > 10) {
                    new_value = '(' + value.substr(0, 2) + ') ' + value.substr(2, 5) + '-' + value.substr(7, 4);
                }

                return new_value;
            },
            weight: function(value) {
                return this.number_with_dots(value) + ' Kg.';
            },
            money: function(value) {
                return 'R$ ' + this.number_with_decimal(value);
            },
            number: function(value) {
                return value.replace(/[^0-9]/g, '');
            },
            number_with_dots: function(value) {
                var value = this.number(value);

                return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ".");
            },
            number_with_decimal: function(value) {
                var new_value = '',
                    value = this.number(value);

                if (value.length <= 0) {
                    new_value = '';
                } else if (value.length <= 2) {
                    new_value = value;
                } else if (value.length > 2) {
                    new_value = this.number_with_dots(value.substr(0, (value.length - 2))) + ',' + value.substr((value.length - 2), 2);
                }

                return new_value;
            }
        },
        getCaret: function(el) {
            var start = 0, end = 0, normalizedValue, range,
                textInputRange, len, endRange;

            if (typeof el.selectionStart == "number" && typeof el.selectionEnd == "number") {
                start = el.selectionStart;
                end = el.selectionEnd;
            } else {
                range = document.selection.createRange();

                if (range && range.parentElement() == el) {
                    len = el.value.length;
                    normalizedValue = el.value.replace(/\r\n/g, "\n");

                    // Create a working TextRange that lives only in the input
                    textInputRange = el.createTextRange();
                    textInputRange.moveToBookmark(range.getBookmark());

                    // Check if the start and end of the selection are at the very end
                    // of the input, since moveStart/moveEnd doesn't return what we want
                    // in those cases
                    endRange = el.createTextRange();
                    endRange.collapse(false);

                    if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
                        start = end = len;
                    } else {
                        start = -textInputRange.moveStart("character", -len);
                        start += normalizedValue.slice(0, start).split("\n").length - 1;

                        if (textInputRange.compareEndPoints("EndToEnd", endRange) > -1) {
                            end = len;
                        } else {
                            end = -textInputRange.moveEnd("character", -len);
                            end += normalizedValue.slice(0, end).split("\n").length - 1;
                        }
                    }
                }
            }

            return {
                start: start,
                end: end
            };
        },
        moveCaret: function(input, distance) {
            if (input.setSelectionRange) {
                input.focus();
                input.setSelectionRange(distance, distance);
            } else if(input.createTextRange) {
                var range = input.createTextRange();
                range.collapse(true);
                range.moveEnd(distance);
                range.moveStart(distance);
                range.select();
            }
        }
    };

    $.fn.addMask = function (type) {
        this.filter('input').each(function () {

            if (typeof AddMask.masks[type] != 'function') {
                return;
            }

            $(this).on('input keyup trymask', function (event) {
                var value = $(this).val(),
                    new_value = '',
                    caret = AddMask.getCaret(this),
                    distance = 0;

                if ((event.type == 'keyup' || event.type == 'input') && value == $(this).data('last-value')) {
                    return;
                }

                new_value = AddMask.masks[type](value);
                $(this).val(new_value).data('last-value', new_value);

                if (typeof caret == 'object' && typeof caret.end == 'number' && event.type == 'keyup') {
                    distance = value.length - caret.end;
                    distance = new_value.length - distance;

                    if (type == 'weight' && distance > (new_value.length - 4)) {
                        distance = new_value.length - 4;
                    }

                    if (type == 'money' && distance <= 4) {
                        distance = 4;
                    }

                    AddMask.moveCaret(this, distance);
                }
            });

            $(this).on('change', function(event) {
                $(this).trigger('trymask');
            });
        });

        return this;
    };
}(jQuery));