JsLint 'out of scope' error

Question

function test(){
    if(true){
        var a = 5;
    }
    alert(a);
}

test();

I keep getting \'out of scope\' errors in my JS code when I check

Answer 1

The code that you wrote is working. It is just not very readable/maintainable. Declaring the variable a inside the scope of the if may give the false impression that a is only visible inside this scope (which, as this program shows, is not true - a will be visible throughout the whole function).

This JsLint warning encourages you to place the declaration at the exact scope where the variable is actually used, as follows:

function test(){
  var a;
  if(true){
      a = 5;
  }
  alert(a);
}