Javascript - variable scope

Question

I am not seeing the issue here. I am new at JavaScript. I have researched variable scope and this looks correct to me. The issue is the variable, useAge, in the legalAge function is undefined. I have it declared before the function and passing it as a parameter to the function.

"use strict";

function person(){
    alert("person function 1");
    var personName = prompt("Enter a name:", "enter name here");
    var personAge = parseInt(prompt("Enter " +  personName + "'s current age:", "enter age here"));
    var votingStatus = legalAge();
    var statusMessage =  (votingStatus == true) ? "old enough" : "not old enough";
    document.writeln("<b>" + personName + " is " + personAge + " years old " + statusMessage + "</b><br />");
    return personAge;   
}


var useAge = person();
alert("useAge: " + useAge);
alert("outside function");

function legalAge(useAge) {
  alert("legalVoting function 2");
  var canVote = (useAge >= 18) ? true : false;  
  alert("Can Vote: " + canVote);
  alert("age: " + useAge);
  return canVote;       
}

person();

You could reduce the canVote line to var canVote = useAge >= 18; — Software Engineer
– Software Engineer, Commented Oct 9, 2014 at 20:03
"and passing it as a parameter to the function." No your a not. — Felix Kling
– Felix Kling, Commented Oct 9, 2014 at 20:11

Scimonster · Accepted Answer · 2014-10-09 20:17:14Z

3

The problem is that you haven't passed personAge into the legalAge() function. You need:

var votingStatus = legalAge(personAge);

Otherwise useAge in legalAge() is undefined and you'll get errors using it.

edited Oct 9, 2014 at 20:17

Scimonster

33.4k10 gold badges79 silver badges92 bronze badges

answered Oct 9, 2014 at 19:59

Software Engineer

16.3k8 gold badges87 silver badges109 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Software Engineer Over a year ago

Thanks for fixing my typo mate :)

user1863593 Over a year ago

Thank you. I passed "personage" into the legalAge() function. I was looking at it like it was being passed with the useAge variable that is = person().

Lotus · Accepted Answer · 2014-10-09 20:03:30Z

0

Couple things to note here:

var useAge = person()

The above line will assign the return value from person() to useAge sure enough...

function legalAge(useAge) {
    ....
}

The above function has a parameter called useAge which is local to the function, and must be passed as an argument when calling the function. I.E. legalAge(10). This would be fine and dandy, except...

function person() {
    ....
    var votingStatus = legalAge();
    ....
}

the person() function is defined to call legalAge() with no parameters. In doing so, legalAge executes and does not have a value for its parameter.

Also, the useAge parameter is different from the global useAge variable.

Hope this helps!

answered Oct 9, 2014 at 20:03

Lotus

2,6561 gold badge23 silver badges22 bronze badges

Collectives™ on Stack Overflow

Javascript - variable scope

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related