Why when sending data over AJAX, do you have to JSON.stringify() your objects?

Question

JSON stands for javascript object notation (as I'm sure you're aware), so why, when sending json via ajax do you need to turn it into a string to send it? Is it simply a formatting thing, or what?

This may belong in another place, if so, let me know, I'll close it and move it.

Obviously, I'm not looking for opinions, I'd like to know the actual answer.

Just to make sure I'm clear, I understand what JSON.stringify() does, and its counterpart JSON.parse(). I just want to know, why using stringify is required.

Thanks!

The reason is: HTTP only knows plain text! Ajax itself is agnostic for special data types, it can be used to send and receive arbitrary data types, which are transmitted as plain text data in the HTTP body. So if JSON is wanted, the text from the HTTP level has to be converted from/to the JSON data format somewhere. — rplantiko
– rplantiko, Commented Sep 14, 2015 at 17:33
What exactly would it mean to send a raw JavaScript object in an HTTP request? — Pointy
– Pointy, Commented Sep 14, 2015 at 17:34
JSON is a string representation of data, similar to XML. Stringify converts JavaScript objects (and arrays) into this string format. — gen_Eric
– gen_Eric, Commented Sep 14, 2015 at 17:35

Quentin · Accepted Answer · 2015-09-14 17:35:59Z

16

when sending json via ajax do you need to turn it into a string to send it?

If it isn't a string, then it isn't JSON in the first place.

JSON is a text based data format. HTTP is a text based communications protocol.

JSON stands for javascript object notation

JSON is based on the syntax for JavaScript literals. A JavaScript object is not JSON.

answered Sep 14, 2015 at 17:35

Quentin

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2 Comments

Jacques Over a year ago

So, while JSON looks like an object literal from JavaScript, it's its own data type, and has to be a string. That's interesting. Appreciate the answer. I'll mark this as correct once it lets me.

Nicolas S.Xu Over a year ago

What do you mean exactly?

alcfeoh · Accepted Answer · 2015-09-14 17:34:51Z

3

AJAX is all about HTTP requests, which are basically "text" requests to a server. That's the main reason why you have to stringify your object: That way it's turned into text that can "travel" over HTTP.

answered Sep 14, 2015 at 17:34

alcfeoh

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Comments

heyfranksmile · Accepted Answer · 2020-01-21 17:00:59Z

0

When sending data to a web server, the data has to be a string.

That's why we are using JSON.stringify() function to convert data to string and send it via XHR request to the server.

        // Creating a XHR object 
        let xhr = new XMLHttpRequest();
        let url = "submit.php"; 

        // open a connection 
        xhr.open("POST", url, true); 

        // Set the request header i.e. which type of content you are sending 
        xhr.setRequestHeader("Content-Type", "application/json"); 

        // Converting JSON data to string 
        var data = JSON.stringify({ "name": name.value, "email": email.value }); 

        // Sending data with the request 
        xhr.send(data);

edited Jan 21, 2020 at 17:00

answered Jan 21, 2020 at 16:50

heyfranksmile

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3 Comments

Jacques Over a year ago

I appreciate your answer, but this is a really old question, and your answer doesn't actually answer the question, it simply restates the question in the answer. It brings no value to the question or other answers. It looks like you're new to stack, so I'll say this: Unless your answer brings something new or valuable to a question, don't post it. Specifically if the question is several years old with a (still valid) accepted answer.

heyfranksmile Over a year ago

You are right. I am new here and I thought that examples would help some other people as well like it did to me. And thanks for the advice though.

Jacques Over a year ago

I agree that examples are helpful, however the example should help answer the question. The example used shows how to send an Ajax request, but the question didn’t ask how to send one, it’s asked why. If this would have been posted when the question was first asked, it probably would have received downvotes.

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