slideCur = 0;
function slideNext() {
	var old = slideCur;
	slideCur = (slideCur + 1 + slideNum) % slideNum;
	slideChg(old);
}
function slidePrev() {
	var old = slideCur;
	slideCur = (slideCur - 1 + slideNum) % slideNum;
	slideChg(old);
}
function slideChg(s1) {
	var s2 = slideCur;
	document.getElementById('slide_pic').src = "images/" + slideImgs[slideCur];
	document.getElementById('slide_page').innerHTML = (slideCur+1) + " of " + slideNum;

	if (document.getElementById('slide_desc_0')) {
		document.getElementById('slide_desc_'+s1).style.display = "none";
		document.getElementById('slide_desc_'+s2).style.display = "block";
		if (document.getElementById('slide_title_0')) {
			document.getElementById('slide_title_'+s1).style.display = "none";
			document.getElementById('slide_title_'+s2).style.display = "block";
		}
	}
	// Old version, for compatibility
	else {
		document.getElementById('slide_title').innerHTML = slideTitles[slideCur];
		document.getElementById('slide_desc').innerHTML = slideDescs[slideCur];
	}
}