function isValidMacAddress(address) {     var c = '';     var i = 0, j = 0;      if ((address.toLowerCase() == 'ff:ff:ff:ff:ff:ff') || (address.toLowerCase() == '00:00:00:00:00:00')) {           alert('error');           return false;     }     var addrParts = address.split(':');     if (addrParts.length != 6) {         alert('error');          return false;     }     for (i = 0; i < 6; i++){          if (addrParts[i] == ''){               alert('error');               return false;          }     }     if (addrParts[i].length != 2) {          alert('error');          return false;     }     for (j = 0; j < addrParts[i].length; j++) {          c = addrParts[i].toLowerCase().charAt(j);          if ((c >= '0' && c <= '9') || (c >= 'a' && c <='f')) {               continue;          } else {               alert('error');               return false;          }     }     if ((parseInt(addrParts[0], 16) % 2) == 1) {          alert('error');          return false;     }     return true;  }