The toString() method is used by a number of built-in functions in the background. It
can be used without fear of causing an error because every object has the method, as it's
inherited from the Object prototype object.
One example of a function that uses the toString() method is the alert() . If an
object is given as an argument to the alert function that isn't a string, it will call
toString() on that object in the background and display the returned string. For ex-
ample, the code:
will display an alert dialog like the one shown in Figure 12.1 .
Figure 12.1. alert() uses toString()
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