$.ajax appending [ ] to the key

Question

I am using Jquery 1.9.1. Having problem in sending ajax data which has array data in one of the key. This is my code:

var obj = {"param1": 1, "param2": 2, "param3": [1, 2]};
$.ajax({
    url : url,
    type: "POST",
    data: obj,
    success: function(){}
});

But when I checked headers in network panel of developer tool. It is displayed as this:

 "param1": 1,
 "param2": 2, 
 **"param3[]"**: [1]
 **"param3[]"**: [2]

Why it is adding [] to the param3 key? Anyone has any idea?

I have used $.ajax before, this the first time it is sending like this.

This is normal behaviour, although it sounds like you may need to use the `traditional: true` property on the AJAX request if you do not want it formatted that way. Check the docs for more info — Rory McCrossan, Nov 20 '15 at 11:32

Niki van Stein · Answer 1 · 2015-11-20T11:36:05.980

1

This is completely correct, this is how arrays are send by a request. It is the same as the html form:

<input name="param3[]" value=1>
<input name="param3[]" value=2>

param3[]: [1], param3[]: [2] is just another notation for the param3 array, in your PHP backend it will be a single variable $_POST['param3'] with the [1,2] as value. (assuming you use PHP, for other languages it will be an similar but perhaps different variable.)

edited Nov 20 '15 at 11:36

answered Nov 20 '15 at 11:32

Niki van Stein

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While you're correct, you're assuming that the OP is using PHP. This would cause the C# MVC model binder to have a fit. – Rory McCrossan Nov 20 '15 at 11:35
@RoryMcCrossan yes I assumed PHP, updated the answer, thanks! – Niki van Stein Nov 20 '15 at 11:36

score 1 · Answer 2 · edited May 23 '17 at 12:15

1

The square bracket (i.e. []) added in jquery 1.4 to handle the multiple dimension array. If you want to remove this you should set the traditional option to true, as shown below:

$.ajaxSettings({traditional: true});

Following link explain the details. issue with brackets in jQuery Form Data when sending data as json

edited May 23 '17 at 12:15

Community

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answered Nov 20 '15 at 12:00

Avinash Jain

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$.ajax appending [ ] to the key

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