Outputting Array Data in JS

Question

I have scoured the internet looking for a working method to achieve what i need to, but had no luck so far.

Basically, I have an AJAX request which runs a database query and echo's everything into a json_encode function doo-dah -> echo json_encode($row);

Now, this is then passed back to my Javascript, and this is where i'm stuck. I need to access the JSON array and select various parts for use to alter input field values dynamically. This is the code i have to run the AJAX request and retrieve the JSON array.

var vars = new XMLHttpRequest();
    vars.onload = function() {
        var retrieved = new Array(this.responseText);
        document.getElementById("testingOutput").innerHTML = retrieved;
};

vars.open("GET", "https://my.url.here", true);
vars.send();

Below is what I have tried with no success (Novice to JS..)

var forename = retrieved['first_name']; // Didn't work
var forename = retrieved[1]; // Didn't work either

I have also tried 'for' loops, which haven't worked either (cannot locate the example i copied off..). I was at first trying to set the retrieved var to just (this.responseText) with no luck either. I literally just need a way that i can pull out parts of the array to stick into some jQuery like below:

$("#firstname").val = forename;
$("#lastname").val = surname;

(where 'forename' and 'surname' are the js variables from the array..)

Any help is appreciated as i am losing my mind!!

EDIT: When i was just using var retrieved = (this.responseText); , when i used typeof it said that the type was a string.. and var retrieved = new Array(this.responseText) comes back as an object.. I'm not sure how to access either.

Answer 1

It looks like you're sending JSON , so you'll need to parse that JSON in your JavaScript to make it into a native object

var retrieved = JSON.parse(this.responseText);

You can read more about JSON.parse here

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As suggested by kiltek it is also a good idea to use console.log or console.dir when debugging so you can view the data structure you are working with