HTML / Javascript : Calculation Form not working . Can't find out why
<p>as I wanted to improve myself , I decided to create a calculation tool for my table top games. I've created an html form and a small script but when I'm clicking on the submit button... Nothing Happens. I've tried PHP instead of Javascript the result was exactly the same. So I wish , you could give me some advice and help me understand why it wasn't working.</p>

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<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
&lt;head&gt;
 &lt;title&gt;The Kiki Meter&lt;/title&gt;
 &lt;link rel="stylesheet" type="text/css" href="apperence.css"&gt;
&lt;/head&gt;
&lt;body&gt;
 &lt;h1&gt;The Kiki Meter&lt;/h1&gt;
 &lt;div&gt;
 &lt;form name="Calculator"&gt;
 Attack Dice Roll : &lt;input type="text" name="Attack_Dice"&gt;
 Defense Dice Roll : &lt;input type="text" name="Defense_Dice"&gt;
 IP : &lt;input type="text" name="IP"&gt;
    Strengh: &lt;input type="text" name="Strengh"&gt;
 Weapon Dmg : &lt;input type="text" name="Weapon_Dmg"&gt;
 &lt;input type="submit" value="Calculer"&gt;
 &lt;/div&gt;
 &lt;script type="text/javascript"&gt;
  var Attack = document.getElementsByName("Attack_Dice");
  var Defense = document.getElementsByName("Defense_Dice");
  var IP = document.getElementsByName("IP");
  var Force = document.getElementsByName("Strengh");
  var Weapon_Dmg = document.getElementsByName("Weapon_Dmg");
  var Success=(Attack-Defense-IP)/100;
  document.write(Success);
  if (Success&lt;0) {
   document.write(Success/(-2));
  }
  else {
   document.write((Force + Weapon_Dmg)*Success); 
  }
 &lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;</code></pre>
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