Калькулятор телепорта IC2

<html>
 <head>
  <style type="text/css">
   .s1 {width: 100px;}
   td {text-align: center;width: 50px;}
   .s2 {text-align: left;width: 350px;}
   input{text-align: center; width: 50px;}
   form{width: 500px;}
   #energu{width: 100px}
  </style>
 </head>
 <body>
  <script src="number_format.js"></script>
  <script lang="JavaScript">
   function calculator(form) {
    if (eval(form.armor.value) == null) {armor = 4; form.armor.value = armor;}else armor = eval(form.armor.value);
    if (eval(form.items.value) == null) {items = 64; form.items.value = items;}else items = eval(form.items.value);
    if (eval(form.x1.value) == null) {x1 = 0; form.x1.value = x1;}else x1 = eval(form.x1.value);
    if (eval(form.x2.value) == null) {x2 = 10; form.x2.value = x2;}else x2 = eval(form.x2.value);
    if (eval(form.y1.value) == null) {y1 = 64; form.y1.value = y1;}else y1 = eval(form.y1.value);
    if (eval(form.y2.value) == null) {y2 = 64; form.y2.value = y2;}else y2 = eval(form.y2.value);
    if (eval(form.z1.value) == null) {z1 = 0; form.z1.value = z1;}else z1 = eval(form.z1.value);
    if (eval(form.z2.value) == null) {z2 = 10; form.z2.value = z2;}else z2 = eval(form.z2.value);
    rast = Math.floor(Math.sqrt((Math.abs(x1 - x2))*(Math.abs(x1 - x2)) + (Math.abs(y1 - y2))*(Math.abs(y1 - y2)) + (Math.abs(z1 - z2))*(Math.abs(z1 - z2))));
    form.total.value = rast;
    weight = Math.floor( 1000 + armor * 100 + 100 * items / 64 );
    form.weight.value = weight;
    energu =  Math.floor( 5 * weight * Math.pow((rast + 10), 0.7));
    form.energu.value = number_format(energu,{decimals: 0, thousands_sep: " "});
   }
  </script>
  <form>
   <table>
    <tr>
     <td class="s2" >&nbsp;</td>
     <td><span>X</span></td>
     <td><span>Y высота</span></td>
     <td><span>Z</span></td>
    </tr>
    <tr>
     <td class="s2"><span lang="ru">Старт</span></td>
     <td><input type="number" name="x1" ></td>
     <td><input type="number" name="y1" ></td>
     <td><input type="number" name="z1" ></td>
    </tr>
     <tr>
     <td class="s2"><span lang="ru">Финиш</span></td>
     <td> <input type="number" name="x2" ></td>
     <td><input type="number" name="y2" ></td>
     <td><input type="number" name="z2" ></td>
    </tr>
     <tr><td class="s2"><span lang="ru">Расстояние</span></td>
     <td><input type="text" name="total" readonly disabled></td>
     <td></td>
     <td>&nbsp;</td>
    </tr>
    <tr>
     <td class="s2"><span lang="ru">Кол-во предметов брони</span></td>
     <td><input type="number" name="armor" pattern="^[ 0-9]+$" ></td>
     <td>&nbsp;</td>
     <td>&nbsp;</td>
    </tr>
    <tr>
     <td class="s2"><span lang="ru">Кол-во предметов в инвентаре, макс 2304</span></td>
     <td><input type="number" name="items" ></td>
     <td>&nbsp;</td>
     <td>&nbsp;</td>
    </tr>
     <tr>
     <td class="s2"><span lang="ru">Вес</span></td>
     <td><input type="text" name="weight" readonly disabled ></td>
     <td colspan="2" ><input type="button" value="Рассчитать" onclick="calculator(this.form)" class="s1" ></td>
    </tr>
    <tr>
     <td class="s2" ><span lang="ru">Затраты энергии</span></td>
     <td colspan="2" > <input type="text" name="energu" id="energu" readonly disabled ></td>
     <td><input type="reset" value="Сброс"></td>
    </tr>
   </table>
  </form>
 </body>
</html>