title: JS Invalid left-hand side expression in postfix operation?
body: <p>I am playing with a javascript and am running into an error.  The error is this:</p>
  
  <p>Invalid left-hand side expression in postfix operation.</p>
  
  <p>And the script is long but I think this is this issue.  The weird thing is this works when I run it locally, but when it is packaged, using asset_packager, it fails.</p>
  
  <p>Any ideas why I might be getting this error?</p>
  
  <p><strong>UPDATE:</strong> After doing more research I found this function.  The error seems to happen after in the "while" statement and I assume it's the "++ + a + ".  This is a plugin so I didn't want to go messing with the code...but do you thing this could be it?</p>
  
  <pre><code>m.getInternetExplorerMajorVersion = function() {
              var a = m.getInternetExplorerMajorVersion.cached = typeof m.getInternetExplorerMajorVersion.cached != "undefined" ? m.getInternetExplorerMajorVersion.cached : function() {
                  var a = 3, b = d.createElement("div"), c = b.getElementsByTagName("i");
                  while ((b.innerHTML = "&lt;!--[if gt IE "++ + a + "]&gt;&lt;i&gt;&lt;/i&gt;&lt;![endif]--&gt;") &amp;&amp; c[0])
  Uncaught ReferenceError: Invalid left-hand side expression in postfix operation
                      ;
                  return a &gt; 4 ? a : !1
              }();
              return a
          }
  </code></pre>