使用php / ajax / json等的未定义数组错误（javascript）

Question

I have a simple website here. It contains a div item with a css object inside. I'm trying to use ajax and json to run a php script that will grab a value out of a text file and update the div item with said value.

Problem is passing dataList[0] to a the function replaceContentInContainer() comes up as an undefined error in console.

Here is the script that is throwing the error. It throws it as soon as dataList[0] is referenced.

<script>
    setInterval(function()
    {
        $.getJSON('loadData.php', function(data){
            var dataList = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
            dataList = data.value;
            var tempID = "tempDIV";
            console.log('Good to go, data was loaded');
            console.log(data);
            ReplaceContentInContainer(tempID,dataList[0]);
        }
    }, 2000);
    </script>

    <script type="text/javascript"><!--
        function ReplaceContentInContainer(id,content) {
        var container = document.getElementById(id);
        container.innerHTML = content;
    }
    //--></script>

the PHP file

<?php
    $lines = file("data.txt");
    echo json_encode($lines);
?>

Data File format 'data.txt'

78\n
82\n
33\n 
etc...

Console output as follows

Good to go, data was loaded indexUpdate.php:30:5
Array [ "75 ", "34 ", "0 ", "0 ", "80 ", "31 ", "60 ", "72 ", "60 ", "70 ", 8 more… ] indexUpdate.php:31:5
TypeError: dataList is undefined
 indexUpdate.php:32:5
Good to go, data was loaded indexUpdate.php:30:5
Array [ "75 ", "34 ", "0 ", "0 ", "80 ", "31 ", "60 ", "72 ", "60 ", "70 ", 8 more… ] indexUpdate.php:31:5
TypeError: dataList is undefined

It doesnt make sense why it thinks my array is undefined or at least why I am not allowed to define the element by a index.

Answer 1

dataList = data.value; should be dataList = data; as you're not returning an object, so there is no value property.