title: Get all functions of an object in JavaScript
body: <p>For example,</p>
  
  <pre><code>Math.mymfunc = function (x) {   
      return x+1;
  }
  </code></pre>
  
  <p>will be treated as a property and when I write</p>
  
  <pre><code>for(var p in Math.__proto__) console.log(p)
  </code></pre>
  
  <p>it will be shown. But the rest of Math functions will not. How can I get all functions of a Math object? </p>