add: if (!formsArray) { return false; } 
context:     okToPrefill: function () {      if (!window._content.document) {        return false;      }      var formsArray = window._content.document.forms;      var form;      for (form=0; form<formsArray.length; form++) {        var elementsArray = formsArray[form].elements;        var element;        for (element=0; element<elementsArray.length; element++) {          var type = elementsArray[element].type;          var value = elementsArray[element].value;          if (type=="" || type=="text" || type=="select-one") {            return true;          }        }      }      return false;    },
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/57f20cd3d16077734e33955b3d73e81bd57770be/nsContextMenu.js/buggy/xpfe/browser/resources/content/nsContextMenu.js