title: How to manipulate DOM with Ruby on Rails
body: <p>As the title said, I have some DOM manipulation tasks. For example, I want to:
  - find all H1 element which have blue color.
  - find all text which have size 12px.
  - etc..</p>
  
  <p>How can I do it with Rails?</p>
  
  <p>Thank you.. :)</p>
  
  <p><strong>Update</strong></p>
  
  <p>I have been doing some research about extracting web page content based on this paper-> <a href="http://www.springerlink.com/index/A65708XMUR9KN9EA.pdf" rel="noreferrer">http://www.springerlink.com/index/A65708XMUR9KN9EA.pdf</a></p>
  
  <p>The summary of the step is:</p>
  
  <ol>
  <li>get the web url which I want to be extracted (single web page)</li>
  <li>grab some elements from the web page based on some visual rules (Ex: grab all <strong>H1 which have blue color</strong>)</li>
  <li>process the elements with my algorithm</li>
  <li>save the result into my database.</li>
  </ol>
  
  <p>-sorry for my bad english-</p>