Added code sample

Author: Angela Molina

5.3-1.js

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+function example() {
+  var local = "Only available inside example()"; // with var
+  global = "Available anywhere once executed"; // without var
+}
+
+console.log(local);
+// "error" (ReferenceError: local is not defined)
+
+console.log(global);
+// "error" (ReferenceError: local is not defined)
+
+example(); // execute the example function
+
+console.log(local);
+// "error" (ReferenceError: local is not defined)
+
+console.log(global);
+// "Also available anywhere"

5.3-2.js

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+var phrase = "always available";
+
+function example() {
+  var local = "Only available inside example()";
+  console.log(phrase);
+  console.log(local);
+}
+
+example();
+// "always available"
+// "Only available inside example()"
+
+console.log(phrase);
+// "always available"
+
+console.log(local);
+// "error" (ReferenceError: local is not defined)

5.3-3.js

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+// one script that uses a counter
+count = 5;
+
+// another script that sets count based on a price
+function thousands(price) {
+  count = price * 1000;
+  return(count);
+}
+thousands(50);
+
+// another script that uses count for an iterator
+for (count = 0; count < 6; count++) {
+  // do something six times
+}
+
+// A whole bunch of code later...
+
+console.log(count);
+// could be anything

5.3-4.js

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+var count = 5;
+
+console.log(count);
+// 5
+console.log(window.count);
+// 5
+
+window.count = 10;
+console.log(count);
+// 10
+console.log(window.count);
+// 10

5.3-5.js

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+// local to a function
+function thousands(price) {
+  var count = price * 1000;
+}
+
+// immediately invoked function expressions 
+(function() { // start a function expression
+  var count;
+  for (count = 0; count < 6; count++) {
+    // do something six times
+  }
+}()); // execute that function expression
+
+// local to a private object (less safe)
+var myApp = {};
+myApp.count = "Hello".length;
+
+console.log(count);
+// error: ReferenceError: count is not defined

5.3-6.js

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+function predefined() {
+  var before = 5; // declared and initialized
+  var after = 10; // declared and initialized
+  return(before + after);
+}
+
+function undefinedAfter() {
+  var before = 5; // declared and initialized
+  return(before + after);
+  var after = 10; // initialized, declaration hoisted
+}
+
+function undeclaredAfter() {
+  var before = 5; // declared and initialized
+  return(before + after);
+}
+
+console.log(predefined());
+// 15
+
+console.log(undefinedAfter());
+// NaN
+
+console.log(undeclarededAfter());
+// error: ReferenceError: after is not defined

5.3.js

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+var greeting = "Hello";
+var items = ["World"];
+
+function greeter(str, arr) {
+  var counter; // local variable in the function
+  for (counter = 0; counter < arr.length; counter++) {
+    console.log(str + " " + arr[counter]);
+  }
+}
+
+greeter(greeting, items);
+// "Hello World"
+
+console.log(counter);
+// "error" (ReferenceError: counter is not defined)