function isDefined(variable) {
    return (typeof(window[variable]) == 'undefined')? false : true;
}

function loadEvents(fieldname) {
    //document.execCommand("BackgroundImageCache", false, true);
    setFocus(fieldname);
    initialiseImages();
   
    if(isDefined("ajaxFunction")) {
        if(!ajaxFunction()) {
            alert("Ajax is not supported in your browser");
        }
    }
}

function setFocus(fieldname) {
    if (fieldname) {
        document.getElementById(fieldname).focus();
    }
}

var images = new Array();
var current_image = 0;
var next_image = 1;
var opacity = 100;      // initial opacity;
var linger = 4000;      // milliseconds to linger on an image
var interval = 50;      // milliseconds to wait between opacity steps
var step = 2;           // opacity step

function initialiseImages() {
    if(document.getElementById("imageContainer")) {
        images = document.getElementById("imageContainer").getElementsByTagName("img");
        setTimeout(pictureFade, linger);
    }
}

function pictureFade() {
    
    if(opacity == 0){
        current_image = ++current_image % images.length;
        next_image = ++next_image % images.length;
        opacity = 100;
        setTimeout(pictureFade, linger);
    }
    else {
        opacity -= step;
        
        images[current_image].style.opacity = opacity/100;
        images[current_image].style.filter = "alpha(opacity = " + opacity + ")";
        images[next_image].style.opacity = (100-opacity)/100;
        images[next_image].style.filter = "alpha(opacity= " + (100 - opacity) + ")";
        
        setTimeout(pictureFade, interval);
    }
}

function getComments() {
    show('comments');
    if(document.getElementById('comment_textarea')) {
        setFocus('comment_textarea');
    }
}

function show(object) {
    document.getElementById(object).style.display='block';
}

function hide(object) {
    document.getElementById(object).style.display='none';
}