function checkForm(form){
    var re=/^([\-_a-zA-Z0-9.]+@[\-_a-zA-Z0-9]+(\.[\-_a-zA-Z0-9]+)+){1}$/i;
    if (form.f_email.value == "" || !re.test(form.f_email.value)){
        alert( "Friends Email address format is invalid!" );
        form.f_email.focus();
        return false;
    }
    if(form.y_name.value == ''){
        alert('Your Name should not be empty!');
        form.y_name.focus();
        return false;
    }
    if (form.y_email.value == "" || !re.test(form.y_email.value)){
        alert( "Your Email address format is invalid!" );
        form.y_email.focus();
        return false;
    }
    if(form.y_message.value == ''){
        alert('Your Message should not be empty!');
        form.y_message.focus();
        return false;
    }
    
    
    return true;
}