?1 判斷select選項中?是否存在Value="paraValue"的Item?
?2 向select選項中?加入一個Item?
?3 從select選項中?刪除一個Item?
?4 刪除select中選中的項?
?5 修改select選項中?value="paraValue"的text為"paraText"?
?6 設置select中text="paraText"的第一個Item為選中?
?7 設置select中value="paraValue"的Item為選中?
?8 得到select的當前選中項的value?
?9 得到select的當前選中項的text?
10 得到select的當前選中項的Index?
11 清空select的項?

js?代碼
// ?1.判斷select選項中?是否存在Value="paraValue"的Item????????
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;????????
} ?????????
???
// ?2.向select選項中?加入一個Item????????
function ?jsAddItemToSelect(objSelect,?objItemText,?objItemValue)? {????????
???? // 判斷是否存在????????
???? if ?(jsSelectIsExitItem(objSelect,?objItemValue))? {????????
????????alert( " 該Item的Value值已經存在 " );????????
????} ? else ? {????????
???????? var ?varItem? = ? new ?Option(objItemText,?objItemValue);??????
????????objSelect.options.add(varItem);?????
????????alert( " 成功加入 " );?????
????} ????????
} ????????
???
// ?3.從select選項中?刪除一個Item????????
function ?jsRemoveItemFromSelect(objSelect,?objItemValue)? {????????
???? // 判斷是否存在????????
???? if ?(jsSelectIsExitItem(objSelect,?objItemValue))? {????????
???????? for ?( var ?i? = ? 0 ;?i? < ?objSelect.options.length;?i ++ )? {????????
???????????? if ?(objSelect.options[i].value? == ?objItemValue)? {????????
????????????????objSelect.options.remove(i);????????
???????????????? break ;????????
????????????} ????????
????????} ????????
????????alert( " 成功刪除 " );????????
????} ? else ? {????????
????????alert( " 該select中?不存在該項 " );????????
????} ????????
} ????
???
???
// ?4.刪除select中選中的項????
function ?jsRemoveSelectedItemFromSelect(objSelect)? {????????
???? var ?length? = ?objSelect.options.length? - ? 1 ;????
???? for ( var ?i? = ?length;?i? >= ? 0 ;?i -- ) {????
???????? if (objSelect[i].selected? == ? true ) {????
????????????objSelect.options[i]? = ? null ;????
????????} ????
????} ????
} ??????
???
// ?5.修改select選項中?value="paraValue"的text為"paraText"????????
function ?jsUpdateItemToSelect(objSelect,?objItemText,?objItemValue)? {????????
???? // 判斷是否存在????????
???? if ?(jsSelectIsExitItem(objSelect,?objItemValue))? {????????
???????? for ?( var ?i? = ? 0 ;?i? < ?objSelect.options.length;?i ++ )? {????????
???????????? if ?(objSelect.options[i].value? == ?objItemValue)? {????????
????????????????objSelect.options[i].text? = ?objItemText;????????
???????????????? break ;????????
????????????} ????????
????????} ????????
????????alert( " 成功修改 " );????????
????} ? else ? {????????
????????alert( " 該select中?不存在該項 " );????????
????} ????????
} ????????
???
// ?6.設置select中text="paraText"的第一個Item為選中????????
function ?jsSelectItemByValue(objSelect,?objItemText)? {????????????
???? // 判斷是否存在????????
???? var ?isExit? = ? false ;????????
???? for ?( var ?i? = ? 0 ;?i? < ?objSelect.options.length;?i ++ )? {????????
???????? if ?(objSelect.options[i].text? == ?objItemText)? {????????
????????????objSelect.options[i].selected? = ? true ;????????
????????????isExit? = ? true ;????????
???????????? break ;????????
????????} ????????
????} ??????????????
???? // Show出結果????????
???? if ?(isExit)? {????????
????????alert( " 成功選中 " );????????
????} ? else ? {????????
????????alert( " 該select中?不存在該項 " );????????
????} ????????
} ????????
???
// ?7.設置select中value="paraValue"的Item為選中????
document.all.objSelect.value? = ?objItemValue;????
???????
// ?8.得到select的當前選中項的value????
var ?currSelectValue? = ?document.all.objSelect.value;????
???????
// ?9.得到select的當前選中項的text????
var ?currSelectText? = ?document.all.objSelect.options[document.all.objSelect.selectedIndex].text;????
???????
// ?10.得到select的當前選中項的Index????
var ?currSelectIndex? = ?document.all.objSelect.selectedIndex;????
???????
// ?11.清空select的項????
document.all.objSelect.options.length? = ? 0 ;???