asp.net enter keyを特定の項目のみ有効にしたい

        form1.Attributes["onkeydown"] = "if(event.keyCode==13){"
                                      + "  if(window.event.srcElement.type!='submit' && "
                                      + "     window.event.srcElement.type!='textarea'){"
                                      + "     if (window.event.srcElement.name!='ctl00$ContentPlaceHolder1$txtREceiveNo'){"
                                      + "       return false;"
                                      + "     }"
                                      + "  }"
                                      + "}";

ただし、ブラウザはＩＥのみ