var rotate_delay = 4000;
current = 0;
function next() {
	if (document.forms['slideform'].slide[current+1]) {
		loading();
		document.images.show.src = document.forms['slideform'].slide[current+1].value;
		document.forms['slideform'].slide.selectedIndex = ++current;
	} else {
		alert('This is the last image.');
	}
	disable();
}
function previous() {
	if (current > 0) {
		loading();
		document.images.show.src = document.forms['slideform'].slide[current-1].value;
		document.forms['slideform'].slide.selectedIndex = --current;
	} else {
		alert('This is the first image.');
	}
	disable();
}
function first() {
	current = 0;
	loading();
	document.images.show.src = document.forms['slideform'].slide[current].value;
	document.forms['slideform'].slide.selectedIndex = current;
	disable();
}
function last() {
	current = document.forms['slideform'].slide.length-1;
	loading();
	document.images.show.src = document.forms['slideform'].slide[current].value;
	document.forms['slideform'].slide.selectedIndex = current;
	disable();
}
function change() {
	loading();
	current = document.forms['slideform'].slide.selectedIndex;
	document.images.show.src = document.forms['slideform'].slide[current].value;
	disable();
}
function loading() {
	document.images.show.src = 'images/loading.gif';
}
function disable() {
	if (!document.forms['slideform']) {
		return false;
	}
	lastnum = document.forms['slideform'].slide.length - 1;
	document.getElementById('b_prev').className = '';
	document.getElementById('b_first').className = '';
	document.getElementById('b_next').className = '';
	document.getElementById('b_last').className = '';

	if (current == 0) {
		document.getElementById('b_prev').className = 'disable';
		document.getElementById('b_first').className = 'disable';
	}
	if (current == lastnum) {
		document.getElementById('b_next').className = 'disable';
		document.getElementById('b_last').className = 'disable';
	}
	var big_image;
	if (big_image = big_images[document.forms['slideform'].slide.selectedIndex]) {
		image = document.images.show.src = document.forms['slideform'].slide[current].value;
		document.getElementById('fullsize').innerHTML = '<a target="_blank" href="'+big_image+'" title="مشاهده ی تصویر در اندازه ی بزرگ">Full Size <img src="images/logo_img.gif" alt="مشاهده ی تصویر در اندازه ی بزرگ" /></a>';
	} else {
		document.getElementById('fullsize').innerHTML = '';
	}
}
function ap(text) {
	document.getElementById('stop').style.display = ( document.getElementById('stop').style.display == 'none' ? '' : 'none');
	document.getElementById('start').style.display = ( document.getElementById('start').style.display == 'none' ? '' : 'none');
	rotate();
}
function rotate() {
	if (document.getElementById('start').style.display == 'none') {
		current = (current == document.forms['slideform'].slide.length-1) ? 1 : current+1;
		document.images.show.src = document.forms['slideform'].slide[current].value;
		document.forms['slideform'].slide.selectedIndex = current;
		window.setTimeout("rotate()", rotate_delay);
		document.getElementById('start').style.display = 'none';
		document.getElementById('stop').style.display = '';
	}
}