title: What is wrong with my JavaScript? It won't compute and display the value I want it to; it's driving me bonkers!
body: <p>What is wrong with my JavaScript?  </p>
  
  <pre><code>&lt;?xml version = "1.0" encoding ="utf-8"?&gt;
  &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1 /DTD/xhtml1-strict.dtd"&gt;
  &lt;html xmlns="http://www.w3.org/1999/xhtml" &gt;
  
   ...
  
  &lt;body&gt; 
     &lt;p&gt;
     &lt;a href="http://nova.umuc.edu/~ct386a28/handson/index.html"&gt;Main Page&lt;/a&gt;
  &lt;/p&gt;
  &lt;h1&gt;GAS MILEAGE CALCULATOR&lt;/h1&gt; 
  
  &lt;form action="" method="post"&gt;
  
  &lt;script type = "text/javascript"&gt;
  
   function mileageCalculator (beginMil, endMil, galCons, form)
   {
  
      var bM = parseFloat(beginMil);
      var eM = parseFloat(endMil);
      var gC = parseFloat(galCons);
  
      if((eM&lt;0)||(bM&lt;0)||(gC&lt;0))
      {
          alert("ERROR: One or more input(s) is negative.");
          form.begMileage = " ";
          form.endMileage = " ";
          form.galConsumed = " ";   
      }
  
      else if ((eM == 0) || (gC == 0))
      {
          alert("ERROR: The end mileage and/or gallon input is zero.");
          form.begMileage = " ";
          form.endMileage = " ";
          form.galConsumed = " ";            
      }
  
      else if (eM &lt; bM)
      {
          alert("ERROR: End mileage is less than begining mileage.");
          form.begMileage = " ";
          form.endMileage = " ";
          form.galConsumed = " ";
      }
      else 
      {                               
          form.mpg.value = ((bM - eM) / gC);  
  
      } 
   }
  
   &lt;/script&gt;
  
  
  
      &lt;div class = "center"&gt;              
          &lt;h3&gt;Enter beginning mileage:&lt;/h3&gt;   
          &lt;input type="text"  name ="begMileage" tabindex="1" /&gt;
          &lt;br /&gt;
          &lt;h3&gt;Enter ending mileage:&lt;/h3&gt;
          &lt;input type="text" name ="endMileage" tabindex="2"  /&gt;
          &lt;br /&gt;
          &lt;h3&gt;Enter gallons consumed:&lt;/h3&gt;
          &lt;input type="text" name ="galConsumed" tabindex="3" /&gt;
          &lt;br /&gt;
  
          &lt;h2&gt;TOTAL MILES PER GALLON&lt;/h2&gt;
          &lt;input type="text" name ="mpg" tabindex="4" /&gt; &lt;br /&gt;
  
      &lt;/div&gt;
  
      &lt;p&gt;&lt;br /&gt;&lt;/p&gt;
  
      &lt;p&gt;         
       &lt;br /&gt;&lt;input type="submit" value="SUBMIT" onclick = "mileageCalculator"/&gt; &lt;input type="reset" value="CLEAR"/&gt; &lt;br /&gt;
      &lt;/p&gt;
  
  &lt;/form&gt;
  </code></pre>
  
  <p>
  </p>