Oa = Oaxy
    and au = auxy
Gardenhire = Gardxy

Parker = Parkxy

Arney = Arnxy

There are 4 rules.
1. The name cuts off at the second vowel and is replaced by 'xy.'
2. connected vowels count as a single and should stay together.
3. EXCEPTION: when the last letter is 'x' another 'x' is not added.
4. Names with only two connected vowels should have "xy" added to the end

function doit(userName) {
        var temp = userName.toLowerCase();
        var vowels = "aeiouy"
        var count = 0;

        if(userName) {
            for(var i=0; i<temp.length; i++) {

                if( vowels.indexOf(temp.charAt(i)) > -1 ) {
                    count++;
                    if(count==1) {
                        while( vowels.indexOf(temp.charAt(++i)) != -1 );
                        i--;
                    } else
                        break;
                }
            }

            userName = userName.substr(0, i);
            if( userName.charAt(userName.length-1) == 's' )
                userName += "y";
            else
                userName += "sy";
        } else
            userName = 'Take a lap, Dummy';
        return userName.toUpperCase();

    }

var word = "anumap";
var transformed = word.replace(/(w+[aeiou]+).*/i, " $1xy");

function doit(userName) {
    var str = userName || "";
    var vowels = ["a","e","i","o","u"];
    var suffix = "xy";

    var str_arr = str.split("");
    var str_arr_rev = str_arr.reverse();

    $.each(str_arr_rev, function (i, item) {
        if ($.inArray(item.toLowerCase(), vowels) > -1) {
            last_vowel_index = i;
            return false;
        }
    });

    if (last_vowel_index == -1) {
        $.each(str_arr_rev, function (i, item) {
            if (item.toLowerCase() == "y") {
                last_vowel_index = i;
                return false;
            }
        });
    }

    if (last_vowel_index > -1)
        str_arr_rev[last_vowel_index] = str_arr_rev[last_vowel_index] + suffix;

    return str_arr_rev.reverse().join("");
}

Oa = Oaxy and au = auxy -Anup

<input type="text" value="" /><br />
   <div id="name"></div>

$(function () {
    $("input").on("change", function(e) {
    $("#name")
        .html(function (index, o) {
        var v = /[aeiou]+.$/gi;
        var o = $(e.target).val();
        var n = v.test(o);
        return (n ? String(o.replace(/[^aeiou]$/gi, "") + "xy").toUpperCase() : o)
    });
   });
})