Two ways to implement Ajax

Let's start with the usual jquery-style Ajax notation, and the value in Java backend

1 /**2 *ajax3  */4 functionShowlasttime () {5     varFacilityId = $ (' *[name= "facilityId"] "). Val ();//Page Values6     varMaintetype = $ ("#mainteType"). Val (); 7     varMAINTEWORKNM = $ ("#mainteWorkNm"). Val (); 8     varurl = ap_base_url + "c412s/showlastymd/";//Generation of URLs9     if(FacilityId! = "" &&maintetype! = "" &&mainteworknm! = ""){Ten $.ajax ({ OneAsyncfalse,//false is synchronous (the user needs to wait for the refresh to be done), true to be asynchronous (no wait required, other operations can be done) AUrl:url,//the requested URL -Type: ' POST ',//two ways post and get,post are invisible, get will spell the parameters and values in the URL (recommended post) - data: { the                 //The following parameters are required to be passed -' FacilityId ': FacilityId, -' Maintetypecd ': Maintetype, -' Mainteworkid ': MAINTEWORKNM +             }, -             //Cache:false, +Errorfunction(XMLHttpRequest, Textstatus, Errorthrown) { A Ajaxerror (XMLHttpRequest, Textstatus, errorthrown); at             }, -Successfunction(data) {//data returned back to the background -$ (". Info"). HTML (data);//What to do after receiving the postback data -             } -         }); -}Else{ in$ (". Info"). Text (""); -     } to     return false; +}

The second is the common JS of the AJAX wording

functionshowLastTime2 () {varMaintetype = $ ("#mainteType"). Val (); varMAINTEWORKNM = $ ("#mainteWorkNm"). Val (); varFacilityId = $ (' *[name= "facilityId"]). Val (); varurl = ap_base_url + "c412s/showlastymd2/"; varXMLHTTP; //Create a XMLHttpRequest object    if(Window. XMLHttpRequest) {//code for ie7+, Firefox, Chrome, Opera, Safarixmlhttp=NewXMLHttpRequest (); }Else{//code for IE6, IE5xmlhttp=NewActiveXObject ("Microsoft.XMLHTTP"); }    if(FacilityId! = "" &&maintetype! = "" &&mainteworknm! = "") {Xmlhttp.open ("POST", URL,false);//send a request to the server, False for synchronization (the user needs to wait for the refresh to be done), true to be asynchronous (no waiting, other operations are possible)Xmlhttp.setrequestheader ("Content-type", "application/x-www-form-urlencoded");//If you must add the line code by using the Post method, add the HTTP header to the requestXmlhttp.send ("maintetypecd=" +maintetype+ "&mainteworkid=" +mainteworknm+ "&facilityid=" +facilityId);//Pass the referenceXmlhttp.onreadystatechange=function(){//trigger Event If server status changes            if(xmlhttp.readystate==4 && xmlhttp.status==200) {//do not understand the following table, to the effect that when the request is complete and the status is OK$ (". Info"). HTML (xmlhttp.responsetext);//Xmlhttp.responsetext values returned for the server            }        }; }Else{        $(". Info"). Text (""); }

Properties	Description
onReadyStateChange	The function (or function name) is called whenever the ReadyState property is changed.
ReadyState	The state of being xmlhttprequest. Vary from 0 to 4. 0: Request not initialized 1: Server Connection established 2: Request received 3: In Request processing 4: The request is complete and the response is ready
Status	$: "OK" 404: Page Not Found

Background Java code value

1  Public String showLastYmd2 (httpservletrequest request HttpServletResponse response) {2     Request.getparameter ("FacilityId");3     request.getparameter ("MAINTETYPECD");4      request.getparameter ("Mainteworkid");5     Response.Write ("Data")    ; // Pass back Parameters 6 }

Two ways to implement Ajax