JAVASCRIPT完全自学手册,中源码的验证修订实例

				
				
				
				22-2  简单的Ajax应用模型
				
				* { font-size:12px; font-family:宋体, Arial; } /*规定了所有的字体样式*/
				body { background-color:buttonface; border-style:none; overflow:auto; }
				fieldset { padding:10px; }
				#txtURL { width:400px; }
				#divState { height:70px; background-color:white; border:1px solid black; overflow:auto; margin:10px; }
				#divResult { height:100px; background-color:white; border:1px solid black; overflow:auto; margin:10px; }
				
				
				var xmlhttp;
				
				function $(str){ return(document.getElementById(str)); }
				
				function getXMLRequester(){
					var xmlhttp_request = false;
					try{
						if( window.ActiveXObject ){
							for( var i = 5; i > -1; i-- ){
								try{
									if( i == 2 ){
										xmlhttp_request = new ActiveXObject( "Microsoft.XMLHTTP" );
									}else{
										xmlhttp_request = new ActiveXObject( "Msxml2.XMLHTTP." + i + ".0" );
									}
									break;
								}catch(e){
									xmlhttp_request = false;
								}
							}
						}else if( window.XMLHttpRequest ){
							xmlhttp_request = new XMLHttpRequest();
						}
					}catch(e){
						xmlhttp_request = false;
					}
					return xmlhttp_request;
				}
				
				function start_navigation(){
				    var url;
				    url = $("txtURL").value;
				    if(!url)return;
				    xmlhttp = getXMLRequester();
				    xmlhttp.onreadystatechange = xmlhttp_onreadystatechange;
				    xmlhttp.open("GET", url, true);
				    log("到\""+url+"\"的连接已打开");
				    xmlhttp.send("");
				    log("数据已发送");
				}
				
				function xmlhttp_onreadystatechange(){
				    log("载入中，XMLHTTP状态：" + xmlhttp.readyState);
				    if(xmlhttp.readyState==4){
				        log("载入完成，服务器返回码\""+xmlhttp.statusText+"\"");
				        if(xmlhttp.status==200){
				            $("divResult").innerText = xmlhttp.responseText;
				        }
				    }
				}
				
				function log(str){
				    var obj = document.createElement("div");
				    var dt = new Date();
				    obj.innerHTML = "["+dt.toLocaleTimeString()+"]: "+str;
				    $("divState").appendChild(obj);
				}
				
				window.onload = function(){
				    $("cmdGo").onclick = start_navigation;
				}
				
				
				
				
				
				    输入 - URL
				    地址：
				    
				    
				
				
				    输出 - 状态信息
				    
				
				
				    输出 - 服务器返回的数据