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<html><body><h1>JavaScript Arrays</h1><p>If you use a named index when accessing an array, JavaScript will redefine the array to a standard object, and some array methods and properties will produce undefined or incorrect results.</p><p id="demo"></p><script>const person = [];person["firstName"] = "John";person["lastName"] = "Doe";person["age"] = 46; document.getElementById("demo").innerHTML =person[0] + " " + person.length;</script></body></html>