1, the input is a string, and the connector of the string is also a plus sign. Finally, it is calculated according to the string, so it is converted into a numerical type first.

integer:c = parse int(a)+parse int(b)

Floating point number: c =parseFloat(a)+parseFloat(b)

2. You can calculate a string and execute the JavaScript code in it.

Level (a+b)

For example:

var a = 1，？

var b = 2，？

var c = a + b，

Thus, the solution of C is 12.

Use the Number () function to solve this problem, as follows:

Var c = number (a)+number (b)?

In this way, the solution of c is 3.

Extended data

Summary of addition operators in Javascript;

1, string+string

var a = ' 10 '，

b = ' 20

console . log(a+b)； ? // 1020

2. String+object

var a = ' 10 '，

b = { _ key:20 }；

console . log(a+b)； ? // 10[ object object]

//Object.prototype.toString () method returns a string representing an object.

3. String+number

var a = ' 10 '，

b = 20

console . log(a+b)； ? // 1020

var a = 10，

b = ' 20

console . log(a+b)； ? // 1020