Eval into js

Question

Why does eval do it?

Answer 1

Пoчему eval так ведет себя в js?
https://code.sololearn.com/Wj8d1SU8TPX9/?ref=app

Answer 2

For string + is contation?

Answer 3

visph great thanks

Answer 4

visph very very thanks for your help

Answer 5

EVALuate a javascript string...

Answer 6

a = "1"
b = "2*2"
alert (eval(a))
// == eval("1") == 1
alert (eval(b))
// == eval("2*2") == 4
alert (eval (a+b))
// == eval("1"+"2*2") == eval("12*2") == 24
alert (eval(b+a))
// == eval("2*2"+"1") == eval("2*21") == 42

Answer 7

everything added to a string should result in a string ;)

if you want to evaluate (a)+(b) as a number sum, you could do:

eval(a)+eval(b)

if a and b result to a number, obviously...

[edit] Friend 4 Goodmen

eval("a+b") // not working, as return string concatenation ^^

Answer 8

yes