Time Input Mask Plugin (jQuery): Code review

I've been searching for a suitable plugin for an input mask for a time field. There are some inherent difficulties with masking a time input, while giving the user the most flexibility.

I have tried to recreate what Google Calendar uses for their time inputs, minus the drop down select. What I've made seems to work, but it's definitely missing a bit of elegance, of bit of beauty, a bit of... je ne sais quoi.

So my challenge for you is to write this code better.

What I have is basically a big ol' bunch of logic statements. I wrote down on a piece of paper all the possible ways I could enter a time, and how I would want to plugin to translate that into a standard "00:00 xm" format.

Here is that list:

• abc => invalid
• abc1:23 => "1:23am"
• 123p => "1:23pm"
• 1 => "1:00am"
• 12 => "12:00am"
• 91 => "9:10am"
• 05 => "5:00pm"
• 123 => "1:23am"
• 170 => invalid
• 013 => invalid
• 1234 => "12:34am"
• 1934 => "7:34pm"
• 9123 => invalid
• 00:12 => "12:12am"
• 1294 => invalid

With that out of the way... here's the plugin code:

/*!
 * jQuery lightweight plugin boilerplate
 * Original author: @ajpiano
 * Further changes, comments: @addyosmani
 * Licensed under the MIT license
 */

;(function ( $, window, document, undefined ) {

    // Create the defaults once
    var pluginName = 'timeMask',
        defaults = {
            propertyName: "value"
        };

    // The actual plugin constructor
    function Plugin( element, options ) {
        this.$el = $(element);

        this.options = $.extend( {}, defaults, options) ;

        this._defaults = defaults;
        this._name = pluginName;
        this._val = this.$el.val();

        this.init();
    }
    // retruns array of numbers in a string

    Plugin.prototype = {
        _getValueInts: function() {
            var ints=[],
                j =0;

            // Get array of number values   
            for(i=0; i<this._val.length; i++) {
                if(parseInt(this._val[i]) >= 0) {
                    ints[j] = parseInt(this._val[i]);
                    j++;
                }
            }
            return ints;    
        },

        _isPM: function() {
            return (this._val.search(/p/gi) >= 0);
        },

        _setInvalid: function() {
            this.$el.addClass('invalid-time');
        },

        _rmInvalid: function() {
            this.$el.removeClass('invalid-time');
        },


        getTimeStr: function() {
            var n = this._getValueInts(),
                pm = this._isPM(),                  // Defaults to false (am)
                time = [0, 0, 0, 0];                // 00:00

            // No n -> invalid
            if(n.length < 1) {
                return false;   
            }

            // Set time array
            else if(n.length == 1) {
                time = [0, n[0], 0, 0];
            }

            else if (n.length == 2) {
                if(n[0] > 1) {                              // "91" => 09:10, 21 => 02:10
                    time = [0, n[0], n[1], 0]
                }
                else if(n[1] >= 6) {                        // "17" => 05:00 pm
                    time = [0, n[1]-2, 0, 0];
                    pm = true;
                }
                else {                                      // "12" => 12:00, "05" => 05:00pm
                    time = [n[0], n[1], 0, 0];
                }
            }

            else if (n.length == 3) {
                if(n[1] >= 6) {                             // "170" => invalid
                    return false;
                }
                else if (n[0] < 1) {                        // "012" => invalid
                    return false;
                }
                else {                                      // "123" => 1:23
                    time = [0, n[0], n[1], n[2]];
                }
            }

            else if (n.length == 4) {
                var hours = n[0]*10 + n[1];

                if (n[2] >= 6) {                            // 12:95
                    return false;
                }
                else if(hours > 24) {
                    return false;
                }
                else if(hours > 12) {                       // "2312" => 11:12pm; hours = 11
                    hours = hours-12;
                    pm = true
                    if(hours >= 10) {
                        time = [1, hours-10, n[2], n[3]];
                    }
                    else {
                        time = [0, hours, n[2], n[3]];
                    }
                }
                else if(n[0] == 0 && n[1] == 0) {           // "00:12" => 12:12 am
                    time = [1, 2, n[2], n[3]];
                    pm = false;
                }
                else {
                    time = [n[0], n[1], n[2], n[3]];
                }
            }

            return "" + ((time[0]==0)? "":time[0]) + time[1] + ":" + time[2] + time[3] + ((!pm)? "am": "pm");
        }, // end getTimeStr()

        _setVal: function(newVal) {
            this.val = newVal;
            this.$el.val(newVal);
        },


        init: function() {
            var _this = this;
            this.$el.bind({
                'focus.timeMask': function() {
                    _this._rmInvalid();
                },
                'blur.timeMask': function() {
                    _this._val = _this.$el.val();
                    var timeStr = _this.getTimeStr()

                    if(!timeStr) {
                        _this._setInvalid();
                    }
                    else {
                        _this._setVal(timeStr);
                    }   
                }
            }); // end this$el.bind
        }, // end init

        /* // This would be nice, but this plugin pattern isn't set up for public methods... 
        destroy: function() {
            console.log('destroying');
            this.$el.unbind('.timeMask');
        }*/

    }; // end Plugin.prototype
    // A really lightweight plugin wrapper around the constructor,
    // preventing against multiple instantiations
    $.fn[pluginName] = function ( options ) {
        return this.each(function () {
            if (!$.data(this, 'plugin_' + pluginName)) {
                $.data(this, 'plugin_' + pluginName,
                new Plugin( this, options ));
            }
        });
    }

})( jQuery, window, document );

I appreciate any and all public rippings/humiliation/etc regarding my code. I'm a bit of an amateur at plugins, and I'm trying to get better at writing well structured code.

On jsFiddle: http://jsfiddle.net/gq8sQ/