title: Retrieve combobox value in javascript
body: <p>This is my little program, what could i do for take the combobox value??</p>
  
  <pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"&gt;
  &lt;html&gt;
  &lt;head&gt;
    &lt;meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"&gt;
    &lt;link rel="stylesheet" type="text/css" href="NewFile.css"&gt;
    &lt;title&gt;Insert title here&lt;/title&gt;
    &lt;script type="text/javascript"&gt;
      function calcola(){
          var op = String(document.getElementById("combo").value);
          alert(op);
      }   
    &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;div class="in"&gt;
      Inserire il primo numero: 
      &lt;input type="text" id="primo"&gt;
      &lt;br&gt;
      Inserire il secondo numero:
      &lt;input type="text" id="secondo"&gt;
    &lt;/div&gt;
    &lt;div class="in"&gt;
      &lt;select id="combo"&gt;
        &lt;option selected="selected"&gt;*&lt;/option&gt;
        &lt;option&gt;/&lt;/option&gt;
        &lt;option&gt;+&lt;/option&gt;
        &lt;option&gt;-&lt;/option&gt;
      &lt;/select&gt;
    &lt;/div&gt;
    &lt;div&gt;
      &lt;input type="button" name="bottone" value="Premi" onclick="calcola();"&gt;
    &lt;/div&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>This program should be a calculator, but I omitted most of code because it's necessary to know the operator befor doing calculations.</p>