Question

I want define defaults for my plugin, this is javascript code:

var opts = {
    'width': 957,
    'height': 590,
    'left': ($(window).width() / 2) - (this.width),
    'top': ($(window).height() / 2) - (this.height)
};​

but opts.left return NaN.
what is problem?

EDIT: I want use width from my object in my object.

Answer 1

this.width isn’t a numeric value.

Origin of NaN values

NaN values are generated when arithmetic operations result in undefined or unrepresentable values. Such values do not necessarily represent overflow conditions. A NaN also results from attempted coercion to numeric values of non-numeric values for which no primitive numeric value is available.

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Update based on the comment:

this isn’t the object, it the caller of the function. so this.width won’t give you the width of the property.

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