jquery ajax example return value detailed explanation_jquery

In JQuery, there are three ways to implement AJAX: $.ajax(), $.post, $.get().
First we look at $.get():

Copy the code The code is as follows:

$.get("test.jsp",
{ name: "cssrain", time: "2008/01/21" }, //Data to be passed
function(data){
alert( "Returned data: " data);
}
)

Then look at $.post():
The format is the same as $.get().

Copy code The code is as follows:

$.post("test.jsp",
{ name: "cssrain", time: "2008/01/21" }, //Data to be transferred
function(data){
alert("Returned data: " data);
}
)

The difference between the above two methods should be the different request methods (one get and one post).
Finally we look at $.ajax():

Copy code The code is as follows:

$.ajax({
url:'Accept.jsp',
type:' post', //Data sending method
dataType:'html', //Accept data formats (there are many here, commonly used ones are html, xml, js, json)
data:'text=' $(" #name").val() '&date=' new Date(), //Data to be passed
error: function(){ //Failure
alert('Error loading document');
},
success: function(msg){ //Success
alert( "Data Saved: " msg );
}
});

Instance
The code for the front-end jsp part is as follows:...
Number of votes:

Copy code The code is as follows:

); href='javascript:;'">Vote

...
The code for the js part is as follows

Copy code The code is as follows:

function myvote(id){
$.post("vote. jsp", { id: id },
function(data){
eval("var data=" data);
if (data.issucc=="0"){
alert( data.mess)
}else{
//alert("Update page");
$("#i" data.myid).html(data.votenum);
}
});
}

The returned data is json
The json data returned by the background is as follows
{issucc:,mess:””,votenum:,myid:}
issucc: whether it was successful
mess: information, mainly error information, such as not logged in, exceeding the limit, etc.
votenum: the total number of votes after voting
myid: the id of the vote, used to update the number of votes on the page
A registration login instance
js
The type returned by login.jsp is in the form of text, which is "OK" when it is correct, and
"error" when it is wrong.

Copy code The code is as follows:

var userName;
var password;
var result;
$(document).ready(function(){
$("#load").hide();
$("#success").hide();
$("#error").hide();
});
$(document).ready(function(){
$("#button").click(function(){
$("#error").hide();
$("#load").show("slow");
userName = $("#userName").val();
password = $("#password").val();
$.ajax({type: "post",
url: "login.jsp",
dataType: "html",
data: "userName=" userName "&password=" password,
success: function(result){
var res = String($.trim(result));
if(res== "OK"){
$("#myTable").hide("slow");
$("#success").show("slow");
}else if(res= ="error"){
$("#error").show("slow");
$("#load").hide("slow");
}else{
alert("Exception returned");}
}
});
});
});

jsp page
First responseText Format

Copy code The code is as follows:

String userName = request.getParameter("userName");
String password = request.getParameter("password");
if(password. equals("longleg")&&userName.equals("thy")){
out.print("OK");
}else{out.print("error");}
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