function disableSubmit(form) {
    var inputs = form.getElementsByTagName('input');
    
    for (var i = 0; i < inputs.length; i++) {
        if (inputs[i].type == 'submit') {
            inputs[i].disabled = true;
            break;
        }
    }
}

function setSubmitEvents() {
    var forms = document.getElementsByTagName('form');
    
    for (var i = 0; i < forms.length; i++) {
        addEvent(forms[i], 'submit', function (e) { disableSubmit(this); })
    }
}

function addEvent(target, event, trigger) {
    if (target.addEventListener) {
        return target.addEventListener(event, trigger, false);
    } else if (target.attachEvent) {
        return target.attachEvent('on' + event, trigger);
    }
    
    return false;
}

addEvent(window, 'load', function (e) { setSubmitEvents(); });