function $(obj, doc)
{
	if (doc)
		return doc.getElementById(obj);
	return document.getElementById(obj);
}

function strlen(str)
{
	var len = 0;
	for (l = 0; l < str.length; l ++)
		if (str.charCodeAt(l) > 255)
			len += 2;
		else
			len ++;
	return len;
}

function createAjax()
{
	if (window.XMLHttpRequest) 
	{
		var xmlHTTP = new XMLHttpRequest();
		return xmlHTTP;
	} 
	else if (window.ActiveXObject) 
	{
		var versions = [
			"MSXML2.XmlHttp.6.0",
			"MSXML2.XmlHttp.3.0"
		];

		for (var i = 0; i < versions.length; i++) 
		{
			try {
				var xmlHTTP = new ActiveXObject(versions[i]);
				return xmlHTTP;
			} catch (error) {}
		}
    	}
	throw new Error("您的浏览器不支持 XMLHttpRequest");
}

var ajaxChange = function ()
{
	if (postAjax.readyState == 4)
	{
		if (postAjax.status == 200)
		{
			if (postAjax.responseText != '')
				alert(postAjax.responseText);
		} else
			alert(postAjax.status);
	}
}

function serverError(code)
{
	alert('网络连接错误,错误代码: ' + code);
}
	
function postMsg(url, msg, change)
{
	var postAjax = createAjax();
	if (postAjax)
	{
		postAjax.open('POST', url, true);
		postAjax.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		if (change)
			postAjax.onreadystatechange = change;
		else
			postAjax.onreadystatechange = function ()
			{
				if (this.readyState != 4) return;
				if (this.status == 200)
				{
					if (this.responseText != '' && this.responseText != 'SUCCEED')
						alert(this.responseText);
				} /*else
						serverError(this.status);*/
			}
		postAjax.send(msg);
	}
	return postAjax;
}

var VISTR = Array('none', 'block');