JavaScript - Write content to any DIV in webpage

Question

I'm trying to build this site dynamically using AJAX. I load the contents for the "content" div from a SQL query, depending on the previouly pressed button. When I press the "Administrar" button, I want to add some buttons to this "adminButtonContainer", but the following error is displayed:

'Cannot read property 'innerHTML' of nullat XMLHttpRequest.ajaxResponse'

In fact, I can only add new content to the "content" DIV. I've been reading something related to calling the JavaScript functions once every DIV has been loaded, but I can't get to understand it. Also, I would like to accomplish it in an "elegant" way, if possible: not having to add tags in the and things like that.

This is my index.html file, which I would like to keep simple:

<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN” “http://www.w3.org/TR/html4/loose.dtd”>
<html>
<head>
    <title></title>
    <meta http-equiv="content-type" content="text/html; charset=utf-8" />
    <script type="text/javascript" src="funciones.js"></script>
    <link rel="stylesheet" type="text/css" href="styles.css">
</head>

<body onload="doAjaxQuery(1,1);">

    <!-- LEFT MENU -->
    <div class="leftMenu">

        <!-- GENERAL BUTTONS -->
        <div class="buttonContainer">
            <button id="inicio" onclick="buttonPressed(1,0);">Inicio</button>
            <button id="artistas" onclick="buttonPressed(2,0);">Artistas</button>
            <button id="albumes" onclick="buttonPressed(3,0);">Álbumes</button>
            <button id="temas" onclick="buttonPressed(4,0);">Temas</button>
            <button id="generos"  onclick="buttonPressed(5,0);">Géneros</button>
            <button id="plataformas" onclick="buttonPressed(6,0);">Plataformas</button>
        </div>

        <!-- ONLY-ADMIN BUTTONS -->
        <div class="adminButtonContainer">
            <button onclick="doAjaxQuery(101,1)">Administrar</button>
        </div>
    </div>

    <div id="content" class="content"></div>

</body>
</html>

And here is the JavaScript function that writes correctly into the "content" DIV, but throws an error in any other DIV:

function ajaxResponse() {

    if (ajaxObject.readyState == 4) {

        if (ajaxObject.status == 200) {

            // JSON Decodification
            var jsonResponse = JSON.parse(ajaxObject.responseText);
            var contentDiv = document.getElementById("content");
            var leftMenuDiv = document.getElementById("leftMenu");
            var buttonsDiv = document.getElementById("buttonContainer");
            var adminButtonsDiv = document.getElementById("adminButtonContainer");

            // innerHTML works with contentDiv
            setNewTitle(jsonResponse.Title);
            contentDiv.innerHTML = "";
            contentDiv.innerHTML += jsonResponse.H1;
            contentDiv.innerHTML += jsonResponse.Body;


            // innerHTML won't work with adminButtonsDiv (or any other but contentDiv):
            // ERROR: 'Cannot read property 'innerHTML' of nullat XMLHttpRequest.ajaxResponse'
            for (let boton of jsonResponse.BotonesAdmin) {
                var bSeccion = boton[1];
                var bBoton  = boton[2];
                adminButtonsDiv.innerHTML += bBoton;
            }

        } else {
            document.write('There was an error. HTTP error code ' + ajaxObject.status.toString() + '.');
            return;
        }
    }
}

Answer 1

Solution 1

ID is missing in this element <div class="adminButtonContainer">

to

<div class="adminButtonContainer" id="adminButtonContainer">

Solution 2:

If you can't add ID then change this JS line to use getElementsByClassName

var adminButtonsDiv = document.getElementById("adminButtonContainer");

to

var adminButtonsDiv = document.getElementsByClassName("adminButtonContainer")[0];

JavaScript - Write content to any DIV in webpage

Question

1 answers

solution1
1 ACCPTED 2017-08-11 08:58:23

JavaScript - Write content to any DIV in webpage

Question

1 answers

solution1 1 ACCPTED 2017-08-11 08:58:23

solution1
1 ACCPTED 2017-08-11 08:58:23