title: Retrieve value of input tag before form is submitted
body: <p>My HTML code has an input tag where the user can enter data (a number).  As soon as they leave that tag (after inputting their data) I need to immediately retrieve that value so I can do some math using the number.  </p>
  
  <p>I plan to use the form event "onchange" (fires the moment when the value of the element is changed) to call a PHP function that will perform the calculation.  All of this needs to happen way before the form is submitted.</p>
  
  <p>I can't figure out how to retrieve the new input tag value using PHP.  Surely the key is via the name attribute of the input tag.</p>
  
  <pre><code>&lt;input type="text" name="numAEBs" value="0" /&gt;
  </code></pre>
  
  <p>The default value is zero.  When the user changes it to something else, how can I retrieve the new value of input tag named "numAEBs"?</p>
  
  <p>Thank you very much for your help with this.</p>