title: Crawl a webpage where the input come from a textbox
body: <p>I want to crawl this site: <a href="https://egov.uscis.gov/casestatus/landing.do" rel="nofollow">https://egov.uscis.gov/casestatus/landing.do</a></p>
  
  <p>My aim is to write a python script that will alert me as soon as the status on this webpage changes, after entering the receipt number. </p>
  
  <p>I have never done this before but did some reading on here: some have recommended <code>urllib2</code> and others <code>scrapy</code>. I have a very very basic understanding of how this works. </p>
  
  <p>But here is my problem: </p>
  
  <p>When I enter a receipt number, the url of the webpage does not change after submission. Looking at the source page, I see where you need to enter the receipt number:</p>
  
  <pre><code>&lt;input id="receipt_number" name="appReceiptNum" class="form-control textbox  initial-focus" maxlength="13" type="text"&gt;`
  </code></pre>
  
  <p>How do I pass this receipt number info into either <code>urllib2</code> or <code>scrapy</code> or any other method. An example of a receipt number is <code>EAC1590674053</code>.</p>
  
  <p>Any pointers greatly appreciated.</p>