function createxmlhttp()
{
    xmlhttpobj = false;
    try{//创建对象，一个一个的试，哎，要是能统一标准都好。。
        xmlhttpobj = new XMLHttpRequest;
    }catch(e){
        try{
            xmlhttpobj=new ActiveXObject("MSXML2.XMLHTTP");
        }catch(e2){
            try{
                xmlhttpobj=new ActiveXObject("Microsoft.XMLHTTP");
            }catch(e3){
                xmlhttpobj = false;
            }
        }
    }
    return xmlhttpobj; 
}


function createXmlHttpRequest()

{
	if (window.XMLHttpRequest)

	{
		var oHttp = new XMLHttpRequest();
		return oHttp;
			}
			else if (window.ActiveXObject)
			{
			var versions =["MSXML2.XmlHttp.6.0","MSXML2.XmlHttp.3.0"];
				for (var i = 0; i < versions.length; i++)
				{
				try
				{
				var oHttp = new ActiveXObject(versions[i]);
				return oHttp;
			}
			catch (error)
		{
		//do nothing here
		}
		}
	}
	return null;
}
 function getsubcategory(bigclassid){
	
	 var X = createxmlhttp();
		 if(X){
			 document.getElementById("subclass").innerHTML="<select name='smallclassid' class='input1'><option value='0' selected>选择二级分类</option></select>";
			  X.onreadystatechange=function(){
			   if(X.readyState==4){
				if(X.status==200){
					//eval(X.responseText)
					var html = X.responseText;//获得返回值

					document.getElementById("subclass").innerHTML=html;
					}
					else{
						//GE('msg').innerHTML=X.statusText
						document.getElementById("subclass").innerHTML="对不起，您请求的页面有问题...";
						}
			   }
			   else{
				   
				   //GE('msg').innerHTML="正在提交数据..."
				   document.getElementById("subclass").innerHTML="加载中，请梢候...";//服务器处理中
				   }
			  };
			X.open('get',"/getsubcategory.asp?bigclassid="+bigclassid+"&number="+Math.random(),true);//get方法 加个随机数。
			X.send(null);
			
			 }
		 else{

			 alert('浏览器不支持XMLHttpRequest');
		 }
		}