var xmlTempResultSearch = xmlResidentListDisplay.selectNodes(
    "//PeopleList/Row[contains(translate(@LastName, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'), '" +
    txtSearch.value + "')]");

PeopleList/Row
  [contains(translate(@LastName,
                     'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
                     'abcdefghijklmnopqrstuvwxyz'), '"
+
           translate(txtSearch.value,
                     'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
                     'abcdefghijklmnopqrstuvwxyz')'"

+ "')]");