<!--

// 获取编码后的当前url
function current_url() {
	return escape(document.location.href);
}

// 显示一个居中窗口
function popup_window(url, name, width, height, features) {
    var left = parseInt((screen.availWidth/2) - (width/2));
    var top = parseInt((screen.availHeight/2) - (height/2));
    var windowFeatures = features + ",width=" + width + ",height=" + height +
        ",left=" + left + ",top=" + top +
        ",screenX=" + left + ",screenY=" + top;
    return window.open(url, name, windowFeatures);
}

// 构造 url，如果 url 中已经包含指定参数则替换参数值
function make_url(key, value, url) {
	var parameters = get_url_args_as_array(url);
	var newurl = "?";
	var key_found = false;

	for (var i = 0; i < parameters.length; i++) {
		if (parameters[i].key == key) {
			key_found = true;
			if (value === null) { continue; }
			parameters[i].value = value;
		}
		if (newurl != "?") {
			newurl += "&";
		}
		newurl += parameters[i].key + "=" + parameters[i].value;
	}

	if (key_found == false && value !== null) {
		if (newurl != "?") {
			newurl += "&";
		}
		newurl += key + "=" + value;
	}
	newurl = newurl.replace('#', '');
	return newurl;
}

// 从 url 中取得全部参数
function get_url_args(url) {
	var pos = url.indexOf('?');
	if (pos == -1) return '';
	return url.substring(pos + 1);
}

// 从 url 中取得全部参数，并以数组形式返回
function get_url_args_as_array(url) {
	var parameters = "&" + get_url_args(url);
	var result = new Array();
	var pos = -1;
	var key = "";
	var value = "";
	do {
		pos = parameters.lastIndexOf("&");
		if (pos == -1) break;
		key = parameters.substring(pos + 1);
		parameters = parameters.substring(0, pos);

		pos = key.indexOf("=");
		if (pos != -1) {
			value = key.substring(pos + 1);
			key = key.substring(0, pos);
		} else {
			value = "";
		}
		result[result.length] = {key:key, value:value};
	} while (pos != -1);

	result.reverse();
	return result;
}

// 从 url 中取得指定参数
function get_url_arg(value_name, url) {
	var parameters = get_url_args(url);
	var pos = parameters.indexOf("?" + value_name + "=");
	if (pos == -1) {
		pos = parameters.indexOf("&" + value_name + "=");
		if (pos == -1) return "";
	}

	var value = parameters.substring(pos + value_name.length + 2);
	pos = value.indexOf("&");
	if (pos == -1) return value;
	return value.substring(0, pos);
}

// -->