eval function in javascript code example

Example 1: javascript execute string code

var theInstructions = "alert('Hello World'); var x = 100";

var F=new Function (theInstructions);

return(F());

Example 2: what is eval in js

The eval() function evaluates JavaScript code represented as a string.

console.log(eval('2 + 2'));
// expected output: 4

console.log(eval(new String('2 + 2')));
// expected output: 2 + 2

console.log(eval('2 + 2') === eval('4'));
// expected output: true

console.log(eval('2 + 2') === eval(new String('2 + 2')));
// expected output: false

Example 3: eval in javascript

eval() -> is able to evalute the things inside it , like eval(a+b+c) , wher a=3,b=4,c=4 , so eval(a+b+c) = 11

Example 4: eval javascript

eval(string)