var a = [1, 2, 3, 4, 5];
document.write("output - 1 : " + a.length);
document.write("<br/>");
a["myKey"] = "myValue";
document.write("output - 2 : " + a.length);
document.write("<br/>");
document.write("output - 3 : " + a);

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.