function splitName(fullname){
    var hyphenated = ['欧阳','太史','端木','上官','司马','东方','独孤','南宫','万俟','闻人','夏侯','诸葛','尉迟','公羊','赫连','澹台','皇甫',
    '宗政','濮阳','公冶','太叔','申屠','公孙','慕容','仲孙','钟离','长孙','宇文','城池','司徒','鲜于','司空','汝嫣','闾丘','子车','亓官',
    '司寇','巫马','公西','颛孙','壤驷','公良','漆雕','乐正','宰父','谷梁','拓跋','夹谷','轩辕','令狐','段干','百里','呼延','东郭','南门',
    '羊舌','微生','公户','公玉','公仪','梁丘','公仲','公上','公门','公山','公坚','左丘','公伯','西门','公祖','第五','公乘','贯丘','公皙',
    '南荣','东里','东宫','仲长','子书','子桑','即墨','达奚','褚师'], // 复姓数组
    var vLength = fullname.length, // 名字长度
    var surname = '';  // 姓氏

    if(vLength > 2){
        //取名字的前两个字,看是否在复姓库中
        var preTwoWords = fullname.substr(0, 2);
        if($.inArray(preTwoWords, hyphenated) > -1){
            surname = preTwoWords;
        }else{
        surname = fullname.substr(0, 1);
    }
    }else if(vLength == 2){//全名只有两个字时,第一个字为姓,第二个字为名
    surnameurname = fullname.substr(0, 1);
    }else{
        surname = fullname;
    }
    // 取得姓氏后长度补*
    while (surname.length < vLength) {
    surname += '*';
}
    return surname;
};

console.log(splitName("我"),splitName("张三"),splitName("欧阳娜娜"),splitName("张楠那"),splitName("诸葛啊")) // 我,张*,欧阳**,张**,诸葛*

如有表述不准确之处,欢迎指正,欢迎补充,感谢阅读。