title: Function trigger twice on modified html
body: <p>I tried on local hosted website, if I modified the data in function on a html page, when I trigger the function, it will be execute for 2 times, 1 time is with default data and another time is is with modified data.</p>
  
  <p>Why this happen?</p>
  
  <p>Will it happen is real website?</p>
  
  <p>If it will happen in real website, is it possible to check modified data or limit it to execute a JavaScript function?</p>
  
  <pre><code>&lt;input type='button' onclick='test("a");' value='try' /&gt;
  &lt;script&gt;function test(text){alert(text);}&lt;/script&gt;
  </code></pre>