function validate_required(field, alerttxt)
{
    with (field)
    {
        if (value == null || value == "")
        {
            alert(alerttxt);
            return false;
        }
        else {
            return true;
        }
    }
}

function validate_email(field, alerttxt)
{
    with (field)
    {
        apos = value.indexOf("@")
        dotpos = value.lastIndexOf(".")
        if (apos < 1 || dotpos - apos < 2)
        {
            alert(alerttxt);
            return false;
        }
        else {
            return true;
        }
    }
}

function validate_password(field, alerttxt) {
    var pos = field.value.indexOf(" ");
    if (pos < 0) {
        if (field.value.length < 6) {
            alert(alerttxt + " : Must be at least 6 characters");
            return false;
        } else {
            return true;
        }
    } else {
        alert(alerttxt + " : Can not contain blank space");
        return false;
    }
}


function validateTextField(field) {
    if (field.length == 0) {
        alert("Field cannot be empty.");
        window.focus(field);
    }
}

function validateEmailField(field) {

    var emailFilter = /^.+@.+\..{2,3,4,6}$/;
    if (!(emailFilter.test(field.value))) {
        alert("Please enter a valid email address.");
        window.focus(field)
    }
}

function validateZipCode(field, alerttxt) {
    with (field) {
        var zipFilter = /\d{5}(-\d{4})?/;
        if (!zipFilter.test(field.value)) {
            alert(alerttxt);
            return false;
        } else {
            return true;
        }
    }
}