Is it ok to declare variables inside of if statements?

Today I’m refactoring someone’s code from var to let which should be used in modern JS and declared variables inside of if statements occur a lot in the code. So this made me wonder is it ok to declare variables inside of if statements or should it be avoided in JS?

var Example1 = "test";

if (Example1 == "test") {
   var test1 = true;
}

if (test1) {
   console.log("Test 1 works!");
}

// Refactored code do not work with let

let Example2 = true;

if (Example2 == "test") {
   let test2 = true;
}

if (test2) {
   console.log("Test 2 works!");
}