function verify()
{
    var field1 = document.getElementById('field1');
    var field2 = document.getElementById('field2');
    var field3 = document.getElementById('field3');

    if (isNaN(field1.value) && isNaN(field2.value) && isNaN(field3.value))
    {
        document.getElementById("warning").innerHTML = 'Please enter your birth date before continuing.';
        return false;
    }

    if (isNaN(field1.value) || isNaN(field2.value) || isNaN(field3.value))
    {
        document.getElementById("warning").innerHTML = 'Please verify your birth date before continuing.';
        return false;
    }

    if (field1.value < 1 || field1.value > 12 || field2.value < 1 || field2.value > 31 || field3.value < 1000 || field3.value > 2012)
    {
        document.getElementById("warning").innerHTML = 'Please verify your birth date before continuing.';
        return false;
    }

    return true;
}


(function() {
    var field1 = document.getElementById('field1');
    var field2 = document.getElementById('field2');
    var field3 = document.getElementById('field3');

    field1.value = 'MM';
    field2.value = 'DD';
    field3.value = 'YYYY';

    field1.onblur = function() {
        if (field1.value == '') {
            field1.value = 'MM';
        }
    };

    field1.onfocus = function() {
        if (field1.value == 'MM') {
            field1.value = '';
        }
    };

    field2.onblur = function() {
        if (field2.value == '') {
            field2.value = 'DD';
        }
    };

    field2.onfocus = function() {
        if (field2.value == 'DD') {
            field2.value = '';
        }
    };

    field3.onblur = function() {
        if (field3.value == '') {
            field3.value = 'YYYY';
        }
    };

    field3.onfocus = function() {
        if (field3.value == 'YYYY') {
            field3.value = '';
        }
    };
})();