How do I call this function in JavaScript?

Question

I am trying to call this function in Javascript but it wont work.

eval("function f() { return x + 1;}")

I called it by typing function f(12);

`function f(x)`. But what book is this? Learning you to use `eval`. — putvande, Jan 13 '14 at 18:57
Rule 1: Don't use `eval`. What problem are you trying to solve? — SLaks, Jan 13 '14 at 18:58
It is telling you that it isn't a good idea to use it right? — putvande, Jan 13 '14 at 19:02

score 0 · Answer 1 · answered Jan 13 '14 at 18:58

0

If you MUST you eval.. you should give x to the function as a parameter. So it should be :

eval("function f(x) { return x + 1;}")

But you could just write it as:

function f(x) { 
    return x + 1;
}

answered Jan 13 '14 at 18:58

putvande

15,068
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score 0 · Answer 2 · answered Jan 13 '14 at 19:15

eval() in javascript

The eval() function evaluates or executes an argument.

If the argument is an expression, eval() evaluates the expression. If the argument is one or more JavaScript statements, eval() executes the statements.

var x = 10;
var y = 20;
var a = eval("x*y") ;
var b = eval("2+2") ;
var c = eval("x+17")";

var res = a + b + c;

Output:

200
4
27

Create your function like this:

function f(x) {
    return x + 1;
}

How do I call this function in JavaScript?

2 Answers2