function checkForm()
{
    var name = $("name");
    var email = $("email");
    var subject = $("subject");
    var message = $("message");
    
    if(name.value.length == 0) 
    {
        alert("Please enter your name.");
        name.focus();
        return false;
    }
    
    if(email.value.length == 0)
    {
        alert("Please enter your email address.");
        email.focus();
        return false;
    }
    
    if(subject.value.length == 0)
    {
        alert("Please enter the subject of your message.");
        subject.focus();
        return false;
    }
    
    if(message.value.length == 0)
    {
        alert("Please enter your message.");
        message.focus();
        return false;
    }
    
    
    return true;
}

function $(id)
{
    return document.getElementById(id);
}