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Asked: 2026-05-14T04:32:08+00:00

For example if I assign var n = document.getElementById(‘A’).childNodes.length; And then later append a

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For example if I assign

var n = document.getElementById('A').childNodes.length;

And then later append a child to A, would n update itself or would I have to assign it the new length again?

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1 Answer

  1. Editorial Team

    No, it will not automatically update itself. The reason is that what you are doing is assigning the value of the length property, which is a number, to the variable n. Hence, n is not aware of the object property it came from, it merely stores a number. Primitive types in JavaScript are assigned/passed by value, whereas objects are passed by reference. This is why doing var o = document.getElementById('A'); would work in the manner you describe – what you’re assigning to o is an object and not a primitive type.

    Note: By “primitive type” I mean any of the following: Undefined, Null, Boolean, Number, or String

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