title: Sudden Javascript error
body: <p>I am developing a project using the standard MVC template in VS 2013.  Suddenly I am getting:</p>
  
  <blockquote>
    <p>Unhandled exception at line 37, column 59140 in
    <a href="https://localhost:44399/a60fbb56d91f49798db3380adaf0a584/browserLink" rel="nofollow">https://localhost:44399/a60fbb56d91f49798db3380adaf0a584/browserLink</a></p>
    
    <p>0x800a139e - JavaScript runtime error: Syntax error, unrecognized
    expression: unsupported pseudo: Label</p>
  </blockquote>
  
  <p>The odd thing is that my project is running at <a href="https://localhost" rel="nofollow">https://localhost</a>:<strong>44302</strong>. Why is the error trapped at port 44399?  Has this something to do with SignalR?</p>
  
  <p>This error is happening in Home/Index and I have commented out all scripts in this page but the error is still happening.  The error code is in <code>browserLink [dynamic]</code>.</p>
  
  <p>What could be the cause?</p>
  
  <hr>
  
  <p>Edits: From the column number of 59,140, this is from minified and obfuscated code. According to Microsoft documentation, browserLink - the ability from the VS debugger to trigger the browser to do a refresh - relies on dynamic code generated on the fly (I don't know from where). I tried to search using fragments from the exception location but couldn't find the code in any of my project files.  Line 37 is more than 110k characters long and is probably the whole jQuery 1.8 file (my project uses jQuery 2.1.3 via Nuget).  I paste a part of it here:</p>
  
  <blockquote>
    <p>/*! jQuery v1.8.2 jquery.com | jquery.org/license */</p>
    
    <p>(function(a,b){function G(a) ....</p>
  </blockquote>
  
  <p>and then:</p>
  
  <blockquote>
    <p>... while(i)f.unshift(i),i=i.parentNode;c=e.length,d=f.length;for(var
    j=0;j&lt;&lt;c&amp;&amp;j&lt;d;j++)if(e[j]!==f[j])return bg(e[j],f[j]);return
    j===c?bg(a,f[j],-1):bg(e[j],b,1)},[0,0].sort(j),m=!k,bc.uniqueSort=function(a){var
    b,c=1;k=m,a.sort(j);if(k)for(;b=a[c];c++)b===a[c-1]&amp;&amp;a.splice(c--,1);return
    a},bc.error=function(a){throw new Error("Syntax error, unrecognized
    expression: "+a)}, ...</p>
  </blockquote>
  
  <p>Column 59,140 is at "throw new Error..."</p>
  
  <hr>
  
  <p>More Edits: I found this at the bottom of the page source:</p>
  
  <pre><code>&lt;!-- Visual Studio Browser Link --&gt;
  &lt;script type="application/json" id="__browserLink_initializationData"&gt;
      {"appName":"Internet Explorer","requestId":"41937a1f698e42ea96530a4b5590d883"}
  &lt;/script&gt;
  &lt;script type="text/javascript" src="https://localhost:44399/a60fbb56d91f49798db3380adaf0a584/browserLink" async="async"&gt;&lt;/script&gt;
  &lt;!-- End Browser Link --&gt;
  </code></pre>
  
  <p>So it seems the error is happening in the browserLink code that is not part of my project. It does not happen in Chrome but only in IE. It was not there with IE for a few weeks before it happened.  It's irritating.</p>