Accidentally Using the Assignment Operator

JavaScript programs may generate unexpected results if a programmer accidentally uses an assignment operator (=), instead of a comparison operator (==) in an if statement.

This if statement returns false (as expected) because x is not equal to 10:

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This if statement returns true (maybe not as expected), because 10 is true:

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This if statement returns false (maybe not as expected), because 0 is false:

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An assignment always returns the value of the assignment.

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