title: I am continually getting a 'Uncaught TypeError: Cannot read property 'value' of null' response and can't figure out why
body: <p>I realize that I am probably looking past something glaringly obvious, but so far I can't seem to find it. I need a second pair of eyes.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
      &lt;head&gt;
      &lt;script type="text/javascript"&gt;
          var t;
          t=document.getElementById('temperture');
          var v;
          v=document.getElementById('speed');
          var h;
          h=document.getElementById('hum');
          function dpOnClick(){
            if (h.value &lt; 50){
              alert('There is no dew point below 50% humidity');}
            else{
              document.getElementById('outputBox').innerHTML='The dew point would be '+  t.value - ((100 - (h.value)/100)/2.778);}
  
      return false;
      }
  
  &lt;/script&gt;
      &lt;title&gt; Weather Indexes &lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;h2&gt;Weather Indexes&lt;/h2&gt;
      &lt;p&gt; Enter degees in fahrenheit and select calculation.&lt;/p&gt;
      &lt;p&gt; Degrees: &lt;input type="number" id="temperture" size=12 value=''&gt; °F &lt;/p&gt;
      &lt;p&gt; Wind Speed: &lt;input type="number" id="speed" size=12 value='' &gt; mph &lt;/p&gt;
      &lt;p&gt; Relative Humidity: &lt;input type="number" id="hum" size=12 value='' &gt;&lt;/p&gt;
  
      &lt;input type="button" value="Dew Point" onclick="dpOnClick();"&gt;
  
      &lt;hr&gt; &lt;div id="outputBox"&gt;&lt;/div&gt; &lt;/hr&gt;
    &lt;/body&gt;
  
  &lt;/html&gt;
  </code></pre>