FirstVal Tolentino Babon's code

<script type='text/javascript'>
function formValidator(){
    var firstname = document.getElementById('firstname');
    var lastname = document.getElementById('lastname');
    var addr = document.getElementById('addr');
    var country = document.getElementById('country');
    var email = document.getElementById('email');
    var number = document.getElementById('number');

    if(isAlphabet(firstname, "Please enter only letters for your name")){
        if(isAlphabet(lastname, "Please enter only letters for your lastname")){
            if(isAlphabet(addr, "Numbers and Letters Only for Address")){
                if(madeSelection(country, "Please Choose a Country")){
                    if(emailValidator(email, "Please enter a valid email address")){
                        if(isNumeric(number, "Please enter numbers only")){
                            return true;
                        }
                    }
                }
            }
        }
    }
    return false;
}
function notEmpty(elem, helperMsg){
    if(elem.value.length == 0){
        alert(helperMsg); elem.focus();
        return false;
    }
    return true;
}

function isNumeric(elem, helperMsg){
    var numericExpression = /^[0-9]+$/;
    if(elem.value.match(numericExpression)){
        return true;
    }else{
        alert(helperMsg);
        elem.focus();
        return false;
    }
}

function isAlphabet(elem, helperMsg){
    var alphaExp = /^[a-zA-Z]+$/;
    if(elem.value.match(alphaExp)){
        return true;
    }else{
        alert(helperMsg);
        elem.focus();
        return false;
    }
}

function isAlphanumeric(elem, helperMsg){
    var alphaExp = /^[0-9a-zA-Z]+$/;
    if(elem.value.match(alphaExp)){
        return true;
    }else{
        alert(helperMsg);
        elem.focus();
        return false;
    }
}

function madeSelection(elem, helperMsg){
    if(elem.value == "Please Choose"){
        alert(helperMsg);
        elem.focus();
        return false;
    }else{
        return true;
    }
}


function emailValidator(elem, helperMsg){
    var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;
    if(elem.value.match(emailExp))
    {
        return true;
    }else{
        alert(helperMsg);
        elem.focus();
        return false;
    }
}
</script>

<form onsubmit='return formValidator()' >
    <table border=1>
        <tr><td>First Name: <td><input type='text' id='firstname' />
        <tr><td>Last Name: <td><input type='text' id='lastname' />
        <tr><td>Date of Birth:<td>
        <select>
            <option>Month</option>
            <option>January</option>
            <option>February</option>
            <option>March</option>
            <option>April</option>
            <option>May</option>
            <option>June</option>
            <option>July</option>
            <option>August</option>
            <option>September</option>
            <option>October</option>
            <option>November</option>
            <option>December</option>
        </select>
        <select>
            <option>Day</option>
            <option>1</option>
            <option>2</option>
            <option>3</option>
            <option>4</option>
            <option>5</option>
            <option>6</option>
            <option>7</option>
            <option>8</option>
            <option>9</option>
            <option>10</option>
            <option>11</option>
            <option>12</option>
            <option>13</option>
            <option>14</option>
            <option>16</option>
            <option>17</option>
            <option>18</option>
            <option>20</option>
            <option>21</option>
            <option>22</option>
            <option>23</option>
            <option>24</option>
            <option>25</option>
            <option>26</option>
            <option>27</option>
            <option>28</option>
            <option>29</option>
            <option>30</option>
            <option>31</option>
        </select>
        <select>
            <option>Year</option>
            <option>2013</option>
            <option>2012</option>
            <option>2011</option>
            <option>2010</option>
            <option>2009</option>
            <option>2008</option>
            <option>2007</option>
            <option>2006</option>
            <option>2005</option>
            <option>2004</option>
            <option>2003</option>
            <option>2002</option>
            <option>2001</option>
            <option>2000</option>
            <option>1999</option>
            <option>1998</option>
            <option>1997</option>
            <option>1996</option>
            <option>1995</option>
            <option>1994</option>
            <option>1993</option>
            <option>1992</option>
            <option>1991</option>
            <option>1990</option>
            <option>1989</option>
            <option>1988</option>
            <option>1987</option>
            <option>1986</option>
            <option>1985</option>
            <option>1984</option>
            <option>1983</option>
            <option>1982</option>
            <option>1981</option>
            <option>1980</option>
        </select>
        <tr><td>Gender:<td><input type="Radio" name="Group1" value="Male" />Male <input type="Radio" name="Group1" value="Female" />Female
        <tr><td>Address:<td><textarea cols="20" rows="5" id='addr'/></textarea>
        <tr><td>Country: <td>
        <select id='country'>
            <option>Choose Country</option>
            <option>Philippines</option>
            <option>United States</option>
            <option>Peru</option>
            <option>Brazil</option>
            <option>India</option>
            <option>Alaska</option>
            <option>Venezuela</option>
            <option>Mexico</option>
            <option>Los Angeles</option>
            <option>Mecaragua</option>
            <option>America</option>
            <option>Australia</option>
            <option>United Kingdom</option>
            <option>Thailand</option>
            <option>United States</option>
        </select>
        <tr><td>Email: <td><input type='text' id='email' />
        <tr><td>Mobile:<td><input type="text" id="number" />
        <tr><td><input type='submit' value='submit' /><input type='reset' value='clear' />
    </table>
</form>