第一種通過<select>的屬性來設(shè)置選中項(xiàng)，此方法可以在動(dòng)態(tài)語言如php在后臺(tái)根據(jù)需要控制輸出結(jié)果。

< select  id =  "sel" >
< option  value = "1" >1</ option >
< option  value = "2"  selected = "selected" >2</ option >
< option  value = "3" >3</ option >
</ select >

第二種為通過前端js來控制選中的項(xiàng):

< script  type = "text/javascript" >
function change(){
     document.getElementById("sel")[2].selected=true;
}
</ script >
< select  id =  "sel" >
< option  value = "1" >1</ option >
< option  value = "2" >2</ option >
< option  value = "3" >3</ option >
</ select >
< input  type = "button"  value = "修改"  onclick = "change()"  />

獲取<select>標(biāo)簽選中項(xiàng)文本的js代碼為:

var  val = document.all.Item.options[document.all.Item.selectedIndex].text
var  i=document.getElementById( 'sel' ).options[document.getElementById( 'sel' ).selectedIndex].value;

一些其它操作<select>標(biāo)簽的技巧如下：

1)動(dòng)態(tài)創(chuàng)建select

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

2)添加選項(xiàng)option

function  addOption(){
//根據(jù)id查找對(duì)象，
var  obj=document.getElementById( 'mySelect' );
//添加一個(gè)選項(xiàng)
obj.add( new  Option( "文本" , "值" ));
}

3)刪除所有選項(xiàng)option

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

4)刪除一個(gè)選項(xiàng)option

function  removeOne(){
var  obj=document.getElementById( 'mySelect' );
//index,要?jiǎng)h除選項(xiàng)的序號(hào)，這里取當(dāng)前選中選項(xiàng)的序號(hào)
var  index=obj.selectedIndex;
obj.options.remove(index);
}

5)獲得選項(xiàng)option的值

var  obj=document.getElementById( 'mySelect' );
var  index=obj.selectedIndex;  //序號(hào)，取當(dāng)前選中選項(xiàng)的序號(hào)
var  val = obj.options[index].value;

6)獲得選項(xiàng)option的文本

var  obj=document.getElementById( 'mySelect' );
var  index=obj.selectedIndex;  //序號(hào)，取當(dāng)前選中選項(xiàng)的序號(hào)
var  val = obj.options[index].text;

7)修改選項(xiàng)option

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

8)刪除select

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

以上就是html中關(guān)于<select>標(biāo)簽如何設(shè)置默認(rèn)選中的選項(xiàng)詳解的詳細(xì)內(nèi)容，更多請(qǐng)關(guān)注php中文網(wǎng)其它相關(guān)文章！