title: How to declare a static variable in Javascript?
body: <p>How to declare a variable that its value can be changed globally by functions?</p>
  
  <pre><code>var a = 0;
  var b = 0;
  
  function c() {a = 5};
  function d() {b = 6};
  
  function e() {console.log(a+b)};
  
  c();
  d();
  e();  // I expect here: 11
  </code></pre>