/* workaround for IE - supporting only old JS */
if(!Array.prototype.indexOf){
    Array.prototype.indexOf=function(obj,start){
        for(var i=(start||0),j=this.length;i<j;i++){
            if(this[i]==obj){return i;}
        }
        return -1;
    }
}
function changeHref(gallery, imgName) {
	var numOfImages = gallery.length - 1;
	function findImgId(array, item) {
		return(array.indexOf(item));
	}
	var imIndex = findImgId(gallery, imgName);
	function runCommandNext(){
		if (numOfImages == imIndex) {
			ajaxpage('show_image_ajax.php?id=' + gallery[numOfImages], 'image_detail'); changeHref(gallery, gallery[numOfImages]);
		} else {
			ajaxpage('show_image_ajax.php?id=' + (gallery[imIndex + 1]), 'image_detail'); changeHref(gallery, gallery[imIndex + 1]);
		}
	}
	function runCommandPrev(){
		if (imIndex == 0) {
			ajaxpage('show_image_ajax.php?id=' + gallery[0], 'image_detail'); changeHref(gallery, gallery[0]);
		} else {
			ajaxpage('show_image_ajax.php?id=' + (gallery[imIndex - 1]), 'image_detail'); changeHref(gallery, gallery[imIndex - 1]);
		}
	}
	var gp = document.getElementById('GalPrev');
	var gn = document.getElementById('GalNext');
	gp.onclick = function() { runCommandPrev(); };
	gn.onclick = function() { runCommandNext(); };
}