title: javascript increment (more than ++) style attribute
body: <p>I'm having some trouble in moving a <code>div</code> tag over with <code>onclick</code>. I can get it to move once but then I don't know how to get the new variable and add to it again.</p>
  
  <p>NO jquery please and I'm not really worried about cross platforms at the moment</p>
  
  <pre><code>function addToMargin()  {
  
          var marginleft = 20;
          document.getElementById("show-sessions").style.marginLeft = marginleft + "px";
  }
  
  #show-sessions  {
          margin-left:10px;
          width:200px;
          overflow:hidden;
  }
  </code></pre>
  
  <p>I tried setting a global variable to store the number in but then it became a <code>NaN</code></p>
  
  <p>any help greatly appreciated...</p>