jstests/function_statements_test.html at master · kreshano/jstests · GitHub

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
  "http://www.w3.org/TR/html4/strict.dtd">
<html>
  <head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <title></title>
  </head>
  <body>
    <script type="text/javascript">
      if (true) {
          function f(){ return 1; }
        }
        else {
          function f(){ return 2; }
        }
        document.write(f() + '<br>');


        document.write((typeof foo) + '<br>'); // "undefined"

          if (true) {
            // once block is entered, `foo` becomes declared and available to the entire scope
            function foo(){ return 1; }
          }
          else {
            // this block is never entered, and `foo` is never redeclared
            function foo(){ return 2; }
          }

          document.write((typeof foo) + '<br>'); // "function"

          if (true) {
            function foo(){ return 1; }
          }
          document.write(foo + '<br>');

          function bar(){ return 1; }
            if (true) {
              // overwritting with function statement
              function bar(){ return 2; }
            }
          function bar(){ return 3; }
          document.write(bar()); // 1 in FF<= 3, 2 in FF3.5 and later
    </script>
  </body>
</html>