var foo = "11" +2+ "1"; Console.log (foo); 1121 Many articles the answer is wrong, I sent to the beginner's friends to see, in order to avoid the beginning to learn the wrong

Experience the difference between adding a string ' 1 ' and subtracting a string ' 1 '

1 var foo = "One" +2-"1"; 2 Console.log (foo);//111 3 console.log (typeof foo); Number

The result of the "11" +2 in the code above is that 112,type is a string, but-"1", which causes Foo to be converted into a numeric type for operation.

12console.log (foo);//11213 console.log (typeof foo); String

The + "1" is simply a concatenation of strings.

We suggest that you use the program to run a look,

var foo = "11" +2+ "1"; Console.log (foo); 1121 Many articles the answer is wrong, I sent to the beginner's friends to see, in order to avoid the beginning to learn the wrong