function validate_contactus(fn,email_send_buttn){
var form = document.forms[fn];
err = '';

if(form.elements['fname'].value == ''){
    err += "Enter First Name.\r\n";
}

if(form.elements['lname'].value == ''){
    err += "Enter Last Name.\r\n";
}

if(form.elements['message'].value == ''){
    err += "Enter Question.\r\n";
}


var email = new RegExp("^.+@.+[\.][a-zA-Z]+$");
if(email.exec(form.elements['email'].value) == null)
{
    err += "Wrong value for email.\r\n";
}


if(err == ''){
    document.getElementById('email_send_buttn').style.color = 'green';
    document.getElementById('email_send_buttn').disabled    = false;
    return true;
}
else{
    document.getElementById('email_send_buttn').style.color = 'red';
    document.getElementById('email_send_buttn').disabled    = true;
    return false;
}

}