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pgmd
6,897 PointsJavascript Foundation Test
In the following code, what value will be displayed in the alert box?
var color = "red";
function example () { var color = "blue"; }
example()
alert(color);
THIS ACTUALLY DOES NOT ALERT ANYTHING AND GIVES AN ERROR
4 Answers
Andrew Mosley
12,328 PointsIt will say red because inside your function you are declaring a new variable named color at the function scope but the alert is calling the variable named color at the global scope.
It is probably throwing an error because your syntax is missing a semicolon.
var color = "red";
function example() {
var color = "blue";
};
example();
alert(color);
pgmd
6,897 PointsActually retested and you are right. It seems though that example(); has no purpose!
Dave McFarland
Treehouse TeacherYou're right, example() doesn't do anything that affects how the script runs. That's the point here -- the idea is to demonstrate that variables created inside a function have their own "scope" and are independent of variables with the same name outside that function. So even though there's a variable named "color" outside the function and the same variable name inside the function, they're actually two different variables.
This is an important concept in JavaScript -- it makes sure that you can write functions that won't interact badly with other functions. This is really handy when you start combining different scripts -- for example multiple jQuery plugins -- on the same page. You need to make sure that variables don't crash into each other and re-write each other's values;
pgmd
6,897 PointsGreat explanation!!! TY
kevinjeffersonsouribio
Courses Plus Student 4,345 PointsT̶h̶e̶r̶e̶ ̶w̶a̶s̶ ̶n̶o̶ ̶r̶i̶g̶h̶t̶ ̶a̶n̶s̶w̶e̶r̶.̶ ̶ ̶R̶e̶s̶t̶a̶r̶t̶e̶d̶ ̶t̶h̶e̶ ̶t̶e̶s̶t̶ ̶o̶v̶e̶r̶ ̶a̶n̶d̶ ̶o̶v̶e̶r̶ ̶a̶g̶a̶i̶n̶,̶ ̶a̶n̶d̶ ̶c̶h̶o̶s̶e̶ ̶e̶v̶e̶r̶y̶ ̶s̶i̶n̶g̶l̶e̶ ̶o̶p̶t̶i̶o̶n̶.̶ ̶N̶o̶n̶e̶ ̶o̶f̶ ̶t̶h̶e̶m̶ ̶w̶e̶r̶e̶ ̶r̶i̶g̶h̶t̶.̶ ̶ ̶I̶ ̶t̶h̶i̶n̶k̶ ̶i̶t̶'̶s̶ ̶a̶ ̶m̶i̶s̶t̶a̶k̶e̶ ̶o̶n̶ ̶t̶h̶e̶ ̶q̶u̶i̶z̶ ̶m̶a̶k̶e̶r̶'̶s̶ ̶p̶a̶r̶t̶.̶
Edit: There was 2 questions regarding the same code. One was missing var and the other has var. There was a right answer.
Dave McFarland
Treehouse TeacherWhich quiz are you referring to? Can you give us the URL of the quiz and the quiz question so we can look into this? Thanks.
kevinjeffersonsouribio
Courses Plus Student 4,345 PointsHi Dave. Sorry about the inconvenience but I just realized I made a mistake when I looked into it again and found out that there was another question very similar to this one on the quiz. And that they both do have right answers. My bad.
Dave McFarland
Treehouse TeacherNo problem Kevin. Glad the quiz works!