function addEvent( obj, type, fn )
{
    if (obj.addEventListener)
        obj.addEventListener( type, fn, false );
    else if (obj.attachEvent)
    {
        obj["e"+type+fn] = fn;
        obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
        obj.attachEvent( "on"+type, obj[type+fn] );
    }
}

function removeEvent( obj, type, fn )
{
    if (obj.removeEventListener)
        obj.removeEventListener( type, fn, false );
    else if (obj.detachEvent)
    {
        obj.detachEvent( "on"+type, obj[type+fn] );
        obj[type+fn] = null;
        obj["e"+type+fn] = null;
    }
}

// Function to determine whether or not to go foward, based on if the email field is empty or not.
function checkEmailBeforeSubmit(event){
    var feedbackForm = document.forms[0];
    var doSubmit = true;

    if(feedbackForm.elements['email'].value==""){
        doSubmit = confirm("We will have no way to respond to your question or comment.\n\nAre you sure you want to submit this feedback without giving us your e-mail address?\nIf so, press \"OK\"");
    }
    if(doSubmit==false){
        if(event.preventDefault){
            event.preventDefault();
        }else{
            event.returnValue = false;
        }
    }
    return doSubmit;
}

// Don't set submit event listener until the form has been loaded
function setupFormClick(){
    var subButton = document.forms[0].elements['submit'];
    addEvent(subButton,'click',checkEmailBeforeSubmit);
}

// Setup listener for submit even loader
addEvent(window,'load',setupFormClick);