title: 7 IHTMLElements - What is their difference?
body: <p>I was trying to extend WatiN functionality and came across these terms - so could anyone please explain what is the difference between <code>IHTMLElement</code>, <code>IHTMLElement2</code>, <code>IHTMLElement3</code>, <code>IHTMLElement4</code>, <code>IHTMLElement5</code>, <code>IHTMLElement6</code> and <code>IHTMLElement7</code>? </p>
  
  <p>What should be used when?<br>
  I see same methods / properties available in some of these objects.<br>
  I was trying to use the <code>removeAttribute</code>, <code>hasAttribute</code> and <code>getBoundingClientRect</code> methods.</p>