The SVGNumber interface correspond to the <number> basic data type.
An SVGNumber object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown.
Documentation for this class was provided by MDN. var value : Float
The value of the given attribute.
Exceptions on setting: a DOMException with code NO_MODIFICATION_ALLOWED_ERR is Raised on an attempt to change the value of a read only attribute.