Why code below sent data as City=Moscow&Age=25 instead of JSON format?
var arr = {City:'Moscow', Age:25};
$.ajax(
{
url: "Ajax.ashx",
type: "POST",
data: arr,
dataType: 'json',
async: false,
success: function(msg) {
alert(msg);
}
}
);
Because you haven't specified neither request content type, nor correct JSON request. Here's the correct way to send a JSON request:
var arr = { City: 'Moscow', Age: 25 };
$.ajax({
url: 'Ajax.ashx',
type: 'POST',
data: JSON.stringify(arr),
contentType: 'application/json; charset=utf-8',
dataType: 'json',
async: false,
success: function(msg) {
alert(msg);
}
});
Things to notice:
JSON.stringify method to convert a javascript object into a JSON string which is native and built-into modern browsers. If you want to support older browsers you might need to include json2.jscontentType property in order to indicate to the server the intent of sending a JSON requestdataType: 'json' property is used for the response type you expect from the server. jQuery is intelligent enough to guess it from the server Content-Type response header. So if you have a web server which respects more or less the HTTP protocol and responds with Content-Type: application/json to your request jQuery will automatically parse the response into a javascript object into the success callback so that you don't need to specify the dataType property.Things to be careful about:
arr is not an array. It is a javascript object with properties (City and Age). Arrays are denoted with [] in javascript. For example [{ City: 'Moscow', Age: 25 }, { City: 'Paris', Age: 30 }] is an array of 2 objects.
Because by default jQuery serializes objects passed as the data parameter to $.ajax. It uses $.param to convert the data to a query string.
From the jQuery docs for $.ajax:
[the
dataargument] is converted to a query string, if not already a string
If you want to send JSON, you'll have to encode it yourself:
data: JSON.stringify(arr);
Note that JSON.stringify is only present in modern browsers. For legacy support, look into json2.js
I wrote a short convenience function for posting JSON.
$.postJSON = function(url, data, success, args) {
args = $.extend({
url: url,
type: 'POST',
data: JSON.stringify(data),
contentType: 'application/json; charset=utf-8',
dataType: 'json',
async: true,
success: success
}, args);
return $.ajax(args);
};
$.postJSON('test/url', data, function(result) {
console.log('result', result);
});
You need to set the correct content type and stringify your object.
var arr = {City:'Moscow', Age:25};
$.ajax({
url: "Ajax.ashx",
type: "POST",
data: JSON.stringify(arr),
dataType: 'json',
async: false,
contentType: 'application/json; charset=utf-8',
success: function(msg) {
alert(msg);
}
});
It gets serialized so that the URI can read the name value pairs in the POST request by default. You could try setting processData:false to your list of params. Not sure if that would help.
datafrom being converted to query string format setprocessData: false. See api.jquery.com/jquery.ajax/#sending-data-to-server