function send_city(city){
		//va 设置给哪个下拉框赋值
		if(document.getElementById("bgDiv") != null){
			var bgObj=document.getElementById("bgDiv");  
			var title=document.getElementById("msgTitle");
			var msgObj=document.getElementById("msgDiv"); 
        	document.body.removeChild(bgObj);   
			document.getElementById("msgDiv").removeChild(title);   
			document.body.removeChild(msgObj);
		}
		

		var u = "weather.jsp?city="+encodeURI(city);
		send_request(u,name_value);
	}
	
	
	
	var http_request;
	
	function send_request(url,meth){
		// 初始化XMLHTTPREQUEST
			if (window.XMLHttpRequest) { // Mozilla, Safari, ... 
			     http_request = new XMLHttpRequest(); 
			} else if (window.ActiveXObject) { // IE 
				 http_request = new ActiveXObject("Microsoft.XMLHTTP"); 
			}	
			
			//设置回掉函数
			
			http_request.onreadystatechange = meth;
			
			// 确定发送请求的方式和 URL 以及是否同步执行下段代码 
			http_request.open("post", url , true); 
			// 设置表头
			http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
			// 发送信息
			http_request.send(null); 
		
	}
	
	function name_value(){
		if(http_request.readyState == 4){
			if(http_request.status == 200){
				var result = http_request.responseText;
				
				document.getElementById("weather").innerHTML = result;
				
			}else{
				//alert("系统正忙请稍侯再试.");
			}
		}
	}
	function Trim(str){
			return str.replace(/(^\s*)|(\s*$)/g, "");
		}