title: Javascript error in IE8: Not implemented
body: <p>This one really puzzles me, as the code looks completely harmless.</p>
  
  <p>IE8 halts script execution with a message:</p>
  
  <blockquote>
    <p>Not implemented.  map.js line:66 char:5 </p>
  </blockquote>
  
  <p>Here is a snip from the code:</p>
  
  <pre><code>63 if(data.map[x] !== undefined &amp;&amp; data.map[x][y] !== undefined) {
  64              
  65   left = (x - data.dim.x_min)*32 + 30;
  66   top = (data.dim.y_max - y)*32 + 30;
  67
  68  /* do stuff */
  XX }
  </code></pre>
  
  <p>debug info:  x:263 data.dim.x_min:263 y:172 data.dim.y_max:174</p>
  
  <p>Data is object returned from JQuery Ajax call. This works in Firefox 3.0 and 3.5, safari 4.0.2 and I've only found this error when viewing the page in IE8. Forcing IE8 into IE7 mode does not make the error go away.</p>
  
  <p>I don't have IE7 to debug with, but I got a tester saying that it doesn't work in IE7 either. </p>