how to store values in an array

Question

In the following code I am getting the scanned value of a barcode.

var scanCode = function () {
window.plugins.barcodeScanner.scan(function(result) {
    alert("Scanned Code: " + result.text + ". Format: " + result.format + ". Cancelled: " + result.cancelled);
    localStorage.setItem("myvalue1", result.text);
    window.location.href = 'page5.html';
    var barcodeVal = localStorage.getItem("myvalue1");
    var test2 = localStorage.getItem("code");
    code = JSON.parse(test2);
    var k = parseInt(localStorage.getItem("counter"));
    document.getElementById(code[k]).innerHTML = barcodeVal;
    alert(code[k]);
    alert(k);
    k++;
    localStorage["counter"] = k;
    localStorage.setItem("code", JSON.stringify(code));
}, function (error) {
    alert("Scan failed: " + error);
});

myvalue1 is the value i am getting from scanning . I have defined an array and a counter in another js file as

localStorage["counter"]=0;
var code = {};
localStorage.setItem("code", JSON.stringify(code));

Now i am trying to store the id in the array code[] and i am trying to print it in page5.html. Above <script> is also defined in the same page5.html. Also i am calling the scan function again and again to get multiple barcode scanned. I am printing the value in the html as

<tr>
    <td>2</td>
    <td id="code[0]"></td>
</tr>

I am getting the error as Cannot set property 'innerHTML' of null . What should i do next? Please help me. thanks in advance

Mauro · Accepted Answer · 2014-06-27 10:26:30Z

1

As you can see from the JsFiddle here when you do the code[k] in the instruction

document.getElementById(code[k]).innerHTML = barcodeVal;

code is not understood as an array of strings but as a string, so poining at code[0] it does not point to your id but to the bracket.

Do a JSON.parse() on your code as in the updated JsFiddle here

answered Jun 27, 2014 at 10:26

Mauro

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16 Comments

Raunak Over a year ago

As i have to save say n number of barcodes in the array. So if i call the array var code = []; like this and in case of declaring id in html like id = "test[0]" and likewise . Is such declaration correct?

Raunak Over a year ago

Your method of declaring the array as var code = ["Test", "Test2"]; is valid for limited set of entries but if i have about 15-20 then what should i do?

Mauro Over a year ago

Javascript arrays accept any number of entry and of mixed types. Define it empty and add them later. You can test it here jsfiddle.net/BygmL/2

Raunak Over a year ago

I declared the way you have told me but still I am getting the error.

Raunak Over a year ago

i have first declared localStorage["counter"]=0; var code = ["Test", "Test2","Test3"]; localStorage.setItem("code", JSON.stringify(code));

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