title: Javascript: fast way to check if form contents have been changed before submission
body: <p>Simple question (I guess)...
  I'm in an "edit-some-element" html form.
  As the page load, the form is filled with current element attributes (eg. name, etc.)
  I could modify some input fields or even decide not to do that but I click the same on submit button because is the only available one.</p>
  
  <p>MY QUESTION:
  is there a property/attribute of the input elements containig the initial input values that I can access to compare them with the current ones when I click on submit button?
  In other words:
  is there a fast way to check if at least one input field has been changed before submitting the form? (so to stop the event if an update isn't really necessary)
  (and I mean "really changed" not considering as changes when I modify something but rewrite it as it was before)</p>
  
  <p>I'd like a minimal example:
  How to check if a simple input-text "name" has been changed</p>
  
  <p>P.S.
  Of course, to trigger the "check-if-something-changed" function,
  if I decide to use pure javascript I would use onSubmit event while using jQuery I would use something like:</p>
  
  <pre><code>$('#formMod').submit(function(){ ...
  </code></pre>
  
  <p>Thanks.</p>