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Piotr Manczak
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Piotr Manczak
Front End Web Development Techdegree Graduate 28,940 Points

If addEventListener() is a function then a variable defined inside addEL is available only within that function?

If addEventListener() is a function then a variable defined inside addEventListener is available only within that function? Do global scope apply in this case?

2 Answers

18,813 Points

JavaScript has function scope, so variables declared within a function become local to that function. A variable declared outside a function would have global scope, and all functions would be able to access it.

// Code here can't use the vorpal variable.
function myFunction() {
  var vorpal = "snicker-snack";
  // Code here can use the vorpal variable.

However, if a value is assigned to a variable that has not been declared, it automatically becomes a global variable.

// Code here can use the jabberwocky variable.
function myFunction() {
  jabberwocky = "wonderland";
  // Code here can also use the jabberwocky variable.

Hopefully that clears it up, but if you're able to link the specific example you're asking about I can give a more detailed explanation.