var rootURL;
var blackScheme = document.getElementById('black');

function getCookie(name, defaultValue) {
	var cookie = '; ' + document.cookie + '; ';
	var prefix = '; ' + name + '=';
	var begin = cookie.indexOf(prefix);

	if (begin == -1) {
		return defaultValue;
	} else {
		var end = cookie.indexOf('; ', begin + 1);
		return unescape(cookie.substring(begin + prefix.length, end));
	}
}

function setCookie(name, value) {
	var expireDate = new Date();
	expireDate.setFullYear(expireDate.getFullYear() + 1);
	document.cookie = name + '=' + escape(value)
		+ '; path=/; expires=' + expireDate.toUTCString();
}

function changeColorScheme() {
	blackScheme.disabled = !blackScheme.disabled;
	setCookie('mystellany', blackScheme.disabled ? 'white' : 'black');
	return false;
}

function createColorSchemeControl() {
	if (blackScheme) {
		var navRow = document.getElementById('nav').rows.item(0);
		var cell = navRow.insertCell(navRow.cells.length);
		cell.style.border = 'none';
		cell.innerHTML = '<a href="#" onclick="return changeColorScheme();"><img src="'
			+ rootURL + 'res/changecolors.gif" width="42" height="16"'
			+ ' alt="Change color scheme" title="Change color scheme"'
			+ ' style="vertical-align: middle;" /></a>';
	}
}

if (blackScheme && getCookie('mystellany', 'black') == 'white') {
	blackScheme.disabled = true;
}