Javascript : Send JSON Object with Ajax?

With jQuery:

$.post("test.php", { json_string:JSON.stringify({name:"John", time:"2pm"}) });

Without jQuery:

var xmlhttp = new XMLHttpRequest();   // new HttpRequest instance xmlhttp.open("POST", "/json-handler");xmlhttp.setRequestHeader("Content-Type", "application/json");xmlhttp.send(JSON.stringify({name:"John Rambo", time:"2pm"}));

If you`re not using jQuery then please make sure:

var json_upload = "json_name=" + JSON.stringify({name:"John Rambo", time:"2pm"});var xmlhttp = new XMLHttpRequest();   // new HttpRequest instance xmlhttp.open("POST", "/file.php");xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");xmlhttp.send(json_upload);

And for the php receiving end:

 $_POST['json_name'] 

I struggled for a couple of days to find anything that would work for me as was passing multiple arrays of ids and returning a blob. Turns out if using .NET CORE I'm using 2.1, you need to use [FromBody] and as can only use once you need to create a viewmodel to hold the data.

Wrap up content like below,

var params = {            "IDs": IDs,            "ID2s": IDs2,            "id": 1        };

In my case I had already json'd the arrays and passed the result to the function

var IDs = JsonConvert.SerializeObject(Model.Select(s => s.ID).ToArray());

Then call the XMLHttpRequest POST and stringify the object

var ajax = new XMLHttpRequest();ajax.open("POST", '@Url.Action("MyAction", "MyController")', true);ajax.responseType = "blob";ajax.setRequestHeader("Content-Type", "application/json;charset=UTF-8");           ajax.onreadystatechange = function () {    if (this.readyState == 4) {       var blob = new Blob([this.response], { type: "application/octet-stream" });       saveAs(blob, "filename.zip");    }};ajax.send(JSON.stringify(params));

Then have a model like this

public class MyModel{    public int[] IDs { get; set; }    public int[] ID2s { get; set; }    public int id { get; set; }}

Then pass in Action like

public async Task<IActionResult> MyAction([FromBody] MyModel model)

Use this add-on if your returning a file

<script src="https://cdnjs.cloudflare.com/ajax/libs/FileSaver.js/1.3.3/FileSaver.min.js"></script>