JS操作select下拉框動態變動(創建/刪除/獲取)

1.動態創建select 

function createSelect(){ 
var mySelect = document.createElement_x("select"); 
mySelect.id = "mySelect"; 
document.body.appendChild(mySelect); 
} 

 

2.添加選項option 

function addOption(){ 
//根據id查找對象， 
var obj=document.getElementByIdx_x('mySelect'); 
//添加一個選項 
obj.add(new Option("文本","值")); 
} 

 

3.刪除所有選項option 

function removeAll(){ 
var obj=document.getElementByIdx_x('mySelect'); 
obj.options.length=0; 
} 

 

4.刪除一個選項option 

function removeOne(){ 
var obj=document.getElementByIdx_x('mySelect'); 
//index,要刪除選項的序號，這里取當前選中選項的序號 
var index=obj.selectedIndex; 
obj.options.remove(index); 
} 

 

5.獲得選項option的值 

var obj=document.getElementByIdx_x('mySelect'); 
var index=obj.selectedIndex; //序號，取當前選中選項的序號 
var val = obj.options[index].value; 

 

6.獲得選項option的文本 

var obj=document.getElementByIdx_x('mySelect'); 
var index=obj.selectedIndex; //序號，取當前選中選項的序號 
var val = obj.options[index].text; 

 

7.修改選項option 

var obj=document.getElementByIdx_x('mySelect'); 
var index=obj.selectedIndex; //序號，取當前選中選項的序號 
var val = obj.options[index]=new Option("新文本","新值"); 

 

8.刪除select 

function removeSelect(){ 
var mySelect = document.getElementByIdx_x("mySelect"); 
mySelect.parentNode.removeChild(mySelect); 
}