BMI Calculator... except BMI won't show up
<p>Good evening, everyone :></p>

<p>I am currently trying to finalize code for a simple BMI calculator. The trouble is that it won't show me a BMI reading when I input my height and weight in my browser. I'm 99% certain that my HTML is solid, it's just the Javascript that seems to be causing problems. Any input I can get on this matter would be appreciated. Thanks!</p>

<pre><code>&lt;!DOCTYPE HTML&gt;
&lt;html&gt;
&lt;head&gt;
&lt;title&gt;BMI Calculator&lt;/title&gt;
&lt;script type="text/javascript"&gt;
/* &lt;![CDATA[ */
function calculate() {

var height = document.getElementById("height");
var weight = document.getElementById("weight") * 703;
var denom = Math.pow(height, 2);
var totalbmi = weight/denom;
var bmi = document.getElementById("bmi");
if (isFinite(bmi)) {        
    bmi.innerHTML = totalbmi.toFixed(2); 
}
}
/* ]]&gt; */
&lt;/script&gt;
&lt;style type="text/css"&gt;
&lt;!--
.result {font-weight: bold; }
--&gt;
&lt;/style&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;form name="details"&gt;
&lt;table&gt;
    &lt;tr&gt;
    &lt;td&gt;Height&lt;br /&gt;
        (in Inches)&lt;/td&gt;
        &lt;td&gt;&lt;input type="text" size="3" id="height"            onChange="calculate();"/&gt;&lt;/td&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
    &lt;td&gt;Weight&lt;br /&gt;
        (in Pounds)&lt;/td&gt;
    &lt;td&gt;&lt;input type="text" size="3" id="weight" onChange="calculate();"/&gt;&lt;/td&gt;
    &lt;/tr&gt;
    &lt;tr&gt;
    &lt;td&gt;&lt;input type="button" value="My BMI" onClick="calculate();"/&gt;&lt;/td&gt;
    &lt;/tr&gt;
  &lt;/table&gt;
&lt;/table&gt;
&lt;table width="270"&gt;
  &lt;tr&gt;
    &lt;td width="104"&gt;Your BMI is:&lt;/td&gt;
    &lt;td width="154"&gt;&lt;input type="text" id="totalbmi"&gt;&lt;/span&gt;&lt;/td&gt;
  &lt;/tr&gt;
&lt;/table&gt;
&lt;/form&gt;
&lt;/body&gt;
&lt;/html&gt; 
</code></pre>
