admin.js fails in IE8

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; InfoPath.2; .NET4.0C)
Timestamp: Tue, 18 Oct 2011 05:54:05 UTC

Message: Object doesn't support this property or method
Line: 32
Char: 13
Code: 0
URI: http://crucible-dev.goharvey.com.au/static/lrss5f/admin.js

        AJS.$(".checkTrailingWhiteSpace").each(function() {
            var text = AJS.$(this).text();
            if (text != text.trim()) {
                AJS.$(this).addClass("trailingWhiteSpace");
                showWhiteSpaceWarning = true;
            }
        });

function __gwt_initWindowCloseHandler(beforeunload, unload) {
  var wnd = window
  , oldOnBeforeUnload = wnd.onbeforeunload
  , oldOnUnload = wnd.onunload;
  
  wnd.onbeforeunload = function(evt) {
    var ret, oldRet;
    try {
      ret = beforeunload();
    } finally {
      oldRet = oldOnBeforeUnload && oldOnBeforeUnload(evt);
    }
    // Avoid returning null as IE6 will coerce it into a string.
    // Ensure that "" gets returned properly.
    if (ret != null) {
      return ret;
    }
    if (oldRet != null) {
      return oldRet;
    }
    // returns undefined.
  };
  
  wnd.onunload = function(evt) {
    try {
      unload();
    } finally {
      oldOnUnload && oldOnUnload(evt);
      wnd.onresize = null;
      wnd.onscroll = null;
      wnd.onbeforeunload = null;
      wnd.onunload = null;
    }
  };
  
  // Remove the reference once we've initialize the handler
  wnd.__gwt_initWindowCloseHandler = undefined;
}