string temp = "http://www.csdn.net/go.html?43483";
            //正则截取
            string id = Regex.Match(temp, @"(?<=\?)\d+").Value;//43483
            //或者Substring
            id = temp.Substring(temp.LastIndexOf("?")+1);//43483

------解决方案--------------------
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C# code
  string temp = "http://www.csdn.net/go.html?43483";
            //正则截取
            string id = Regex.Match(temp, @"(?<=\?)\d+").Value;//43483
            //或者Substring
            id = t……


------解决方案--------------------

你也可以分割字符串把。当前页面 http://www.csdn.net/go.html?43483  
var url = location。href；
var para = url.split('?');
var link='http://www.baidu.com/absd/stID_';
window.location.href=link+para[1]