js动态改变select选择变更option的index值示例

document.getElementById("louyuming").options[0].selected=true; function jsSelectIsExitItem(objSelect, objItemValue) { var isExit = false; for (var i = 0; i < objSelect.options.length; i++) { if (objSelect.options[i].value == objItemValue) { isExit = true; break; } } return isExit; } Javascript 操作