title: Invalid Expression Term '='
body: <p>Sorta just messing with javascript and hoping that this would work..</p>
  
  <p>Using asp.net textboxes and trying to change the values of the disabled ones with the math calculations of the enabled ones.. I thought maybe I was concatenating and that was the 
  error but it's not even hitting the math, skipping straight from ().value = to the error..</p>
  
  <p>The error is hitting on page load before I get to do anything and my button has:</p>
  
  <pre><code>&lt;input type="button" onclick="chkMath()"/&gt;
  </code></pre>
  
  <p>I did try an asp button too but that didn't work so this is what I have for now.</p>
  
  <p>Here is my script:</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
      function chkMath() {
          // cust id doesn't need variable
          // var a = document.getElementById('&lt;%=f0.ClientID%&gt;').value;
          var b = document.getElementById('&lt;%=f1.ClientID%&gt;').value;
          var c = document.getElementById('&lt;%=f2.ClientID%&gt;').value;
          var d = document.getElementById('&lt;%=f4.ClientID%&gt;').value;
          var e = document.getElementById('&lt;%=f5.ClientID%&gt;').value;
          var f = document.getElementById('&lt;%=f6.ClientID%&gt;').value;
          var g = document.getElementById('&lt;%=f8.ClientID%&gt;').value;
          var h = document.getElementById('&lt;%=f9.ClientID%&gt;').value;
          var i = document.getElementById('&lt;%=f11.ClientID%&gt;').value;
          var j = document.getElementById('&lt;%=f12.ClientID%&gt;').value;
  
          document.getElementById('&lt;%#=f3.ClientID%&gt;').value = b - c;
          document.getElementById('&lt;%#=f7.ClientID%&gt;').value = e + f;
          document.getElementById('&lt;%#=f10.ClientID%&gt;').value = g + h;
          document.getElementById('&lt;%#=f13.ClientID%&gt;').value = b - i;
          document.getElementById('&lt;%#=f14.ClientID%&gt;').value = d - j;
      }
  &lt;/script&gt;
  </code></pre>
  
  <p>Using the getElementByID(''); syntax I found on asp.net</p>
  
  <p>Anyway don't know what's going on here, any help is appreciated.</p>