JavaScript ReferenceError – Reference to undefined property “x”

0 0 1 minute read

This JavaScript warning reference to undefined property occurs if a script tries to access an object property that doesn’t exist.

Message:

ReferenceError: reference to undefined property "x" (Firefox)

Error Type:

ReferenceError(Only reported by firefox browser)

Cause of the error: The script is trying to access an object property that doesn’t exist.

Example 1: In this example, the valid property is accessed, So the error has not occurred.

HTML

<!DOCTYPE html>
<html>
<head>
    <script src=
"https://code.jquery.com/jquery-3.5.0.js">
    </script>
</head>
 
<body style="text-align: center;">
    <h1 style="color: green;">
        zambiatek
    </h1>
    <p>
        JavaScript ReferenceError
        Reference to undefined property
    </p>
    <button onclick="Geeks();">
        click here
    </button>
    <p id="GFG_DOWN"></p>
 
    <script>
        let el_down = document.getElementById("GFG_DOWN");
        function GFG() {
            "use strict";
            let AR_GFG = { prop_1: "Val_1" };
            return AR_GFG.prop_1;
        }
        function Geeks() {
            try {
                GFG();
                el_down.innerHTML =
                    "'Reference to undefined property'" +
                    " error has not occurred";
            } catch (e) {
                el_down.innerHTML =
                    "'Reference to undefined property'" +
                    "error has occurred";
            }
        }
    </script>
</body>
</html>

Output:

Example 2: In this example, the undefined property is accessed, So the error has occurred.

HTML

<!DOCTYPE html>
<html>
 
<head>
    <script src=
"https://code.jquery.com/jquery-3.5.0.js">
    </script>
</head>
 
<body style="text-align: center;">
    <h1 style="color: green;">
        zambiatek
    </h1>
 
    <p>
        JavaScript ReferenceError
        Reference to undefined property
    </p>
 
    <button onclick="Geeks();">
        click here
    </button>
    <p id="GFG_DOWN"></p>
 
    <script>
        let el_down = document.getElementById("GFG_DOWN");
        function GFG() {
            "use strict";
            let GFG = {};
            return GFG.prop1;
        }
        function Geeks() {
            try {
                GFG();
                el_down.innerHTML =
                    "'Reference to undefined property'" +
                    "error has not occurred";
            } catch (e) {
                el_down.innerHTML =
                    "'Reference to undefined property'" +
                    "error has occurred";
            }
        }
    </script>
</body>
</html>

Output:

Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, zambiatek Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!