Pass JSON in Javascript variable into a JQuery post

Question

I am trying to get some data from a remote location by a JQuery post. It works great when I hardcode the data to post, but doesn't work when I put the JSON in a javascript variable, and then pass it in. As far as I understand, a JSON is just a string, so I'm not sure what the difference is.

so, this works:

$.post( PostURL, {var:"somevalue"}, function( data ) {
  // do something with data
}

but this doesn't:

jsonstring = '{var:"somevalue"}';

$.post( PostURL, jsonstring, function( data ) {
  // do something with data
}

obviously, I'm going to need to send different variables to get the stuff I need, so it can't be hard-coded. What am I doing wrong?

First example is an object, second is a string. You're not just putting it in a variable, you are changing its type. — spenibus
– spenibus, Commented Aug 19, 2015 at 3:48
@spenibus Thanks, didn't realize I had left quotes off the top one, changing the type and accidentally making it work. XD — Skeets
– Skeets, Commented Aug 19, 2015 at 4:10

spenibus · Accepted Answer · 2015-08-19 04:06:48Z

2

Data in post() doesn't take JSON as an argument but an object, which is why the first code works. Your second code is using JSON, which is a string representation of an object rather than an actual object, therefore invalid.

jQuery.post( url [, data ] [, success ] [, dataType ] )

url
Type: String
A string containing the URL to which the request is sent.

data
Type: PlainObject or String
A plain object or string that is sent to the server with the request.

http://api.jquery.com/jquery.post/

Note that while it says that data can take a string, it is of the form key=value&key=value.

You don't need JSON, simply store the object in your variable rather than converting it to a string.

var myData = {var:"somevalue"};
$.post(PostURL, myData, function(data) {
    // do something with data
});

edited Aug 19, 2015 at 4:06

answered Aug 19, 2015 at 4:00

spenibus

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1 Comment

Skeets Over a year ago

This answer helped me make the cleanest code (no juggling between string and JSON object), and it works. Thanks.

AdityaParab · Accepted Answer · 2015-08-19 03:59:09Z

0

jsonstring =  JSON.parse('{var:"somevalue"}');

$.post( PostURL, jsonstring, function( data ) {
  // do something with data
}

answered Aug 19, 2015 at 3:59

AdityaParab

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