title: Get value from HTML input form with PHP
body: <p>I am wanting to literally take the HTML form input with the ID "bet" and after the value has been entered and submitted; get the exact input for example: '100' may be entered, as I am wanting to perform an if statement to check that the value submitted isn't less than 0 for obvious reasons so then I can stop the webpage proceeding to perform the bet, and make the user instead enter a valid amount.</p>
  
  <p>The code that I am having an issue with is below, upon loading the page I am getting the error: Notice: Undefined index: bet</p>
  
  <pre><code>&lt;form action="duel.php" name="duel" id="duel"&gt;
  &lt;input type="text" id="betamount" name="betamount"&gt;
  &lt;?php
  $data = $_GET['betamount'];
  echo $data;
  ?&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>I am fairly new to programming in PHP, so any help would be greatly appreciated.</p>