HTML select option detailed description
This article introduces the detailed explanation of HTML select option
javascriptThe detailed explanation of HTML (select option)
1. Basic understanding:
var e = document.getElementById("selectId");
e. options= new Option("text","value");
//Create an option object, that is, create one or more
/ in the
onclick="number() ;">
1. Dynamically create select
function createSelect(){
var mySelect = document.createElement("select");
mySelect.id = "mySelect";
document.body.appendChild(mySelect);
}
2 .Add option option
function addOption(){
//Find the object based on id,
var obj=document.getElementById('mySelect');
/ /Add an option
obj.add(new Option("text","value")); //This is only valid in IE
obj.options.add(new Option("text"," value")); //This is compatible with IE and firefox
}
3. Delete all options option
function removeAll(){
var obj=document.getElementById('mySelect');
obj.options.length=0;
}
4. Delete an option option
function removeOne(){
var obj=document.getElementById('mySelect');
//index, the serial number of the option to be deleted, take here The serial number of the currently selected option
var index=obj.selectedIndex;
obj.options.remove(index);
}
5. Get the value of option
var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options [index].value;
6. Get the text of option option
var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options[index].text;
7. Modify the option option
var obj=document. getElementById('mySelect');
var index=obj.selectedIndex; //Serial number, take the serial number of the currently selected option
var val = obj.options[index]=new Option(" New text","new value");
8. Delete select
function removeSelect(){
var mySelect = document.getElementById("mySelect");
mySelect .parentNode.removeChild(mySelect);
}
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//ZH-CN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html">
<head>
<script language=JavaScript>
function $(id)
{
return document.getElementById(id)
}
function show()
{
var selectObj=$("area")
var myOption=document.createElement("option")
myOption.setAttribute("value","10")
myOption.appendChild(document.createTextNode("上海"))
var myOption1=document.createElement("option")
myOption1.setAttribute("value","100")
myOption1.appendChild(document.createTextNode("南京"))
selectObj.appendChild(myOption)
selectObj.appendChild(myOption1)
}
function choice()
{
var index=$("area").selectedIndex;
var val=$("area").options[index].getAttribute("value")
if(val==10)
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
var sh=document.createElement("select")
sh.add(new Option("浦东新区","101"))
sh.add(new Option("黄浦区","102"))
sh.add(new Option("徐汇区","103"))
sh.add(new Option("普陀区","104"))
$("context").appendChild(sh)
}
if(val==100)
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
var nj=document.createElement("select")
nj.add(new Option("玄武区","201"))
nj.add(new Option("白下区","202"))
nj.add(new Option("下关区","203"))
nj.add(new Option("栖霞区","204"))
$("context").appendChild(nj)
}
}
function calc()
{
var x=$("context").childNodes.length-1;
alert(x)
}
function remove()
{
var i=$("context").childNodes.length-1;
var remobj=$("context").childNodes[i];
remobj.removeNode(true)
}
</script>
<body>
<p id="context">
<select id="area" on
change="choice()">
</select>
</p>
<input type=button value="显示" onclick="show()">
<input type=button value="计算结点" onclick="calc()">
<input type=button value="删除" onclick="remove()">
</body>
</html>
Based on these things, I used JQEURY AJAX+JSON to implement a small function as follows:
JS code: (only the code related to SELECT is taken)
/**
* @description 构件联动下拉列表 (用JQUERY 的AJAX配合JSON实现)
* @prarm selectId 下拉列表的ID
* @prarm method 要调用的方法名称
* @prarm temp 此处存放软件ID
* @prarm url 要跳转的地址
*/
function linkAgeJson(selectId,method,temp,url){
$j.ajax({
type: "get",//使用get方法访问后台
dataType: "json",//返回json格式的数据
url: url,//要访问的后台地址
data: "method=" + method+"&temp="+temp,//要发送的数据
success: function(msg){//msg为返回的数据，在这里做数据绑定
var data = msg.lists;
coverJsonToHtml(selectId,data);
}
});
}
/**
* @description 将JSON数据转换成HTML数据格式
* @prarm selectId 下拉列表的ID
* @prarm nodeArray 返回的JSON数组
*
*/
function coverJsonToHtml(selectId,nodeArray){
//get select
var tempSelect=$j("#"+selectId);
//clear select value
isClearSelect(selectId,'0');
var tempOption=null;
for(var i=0;i<nodeArray.length;i++){
//create select Option
tempOption= $j('<option value="'+nodeArray[i].dm+'">'+nodeArray[i].mc+'</option> ');
//put Option to select
tempSelect.append(tempOption);
}
// 获取退化构件列表
getCpgjThgl(selectId,'thgjDm');
}
/**
* @description 清空下拉列表的值
* @prarm selectId 下拉列表的ID
* @prarm index 开始清空的下标位置
*/
function isClearSelect(selectId,index){
var length=document.getElementById(selectId).options.length;
while(length!=index){
//长度是在变化的，因为必须重新获取
length=document.getElementById(selectId).options.length;
for(var i=index;i<length;i++)
document.getElementById(selectId).options.remove(i);
length=length/2;
}
}
/**
* @description 获取退化构件列表
* @prarm selectId1 引用软件下拉列表的ID
* @prarm selectId2 退化构件下拉列表的ID
*/
function getCpgjThgl(selectId1,selectId2){
var obj1=document.getElementById(selectId1);//引用软件下拉列表
var obj2=document.getElementById(selectId2);//退化构件下拉列表
var len=obj1.options.length;
//当引用软件列表长度等于1时返回，不做操作
if(len==1){
return false;
}
//清空下拉列表的值，两种方式都可以
// isClearSelect(selectId2,'1');
document.getElementById(selectId2).length=1;
for(var i=0;i<len; i++){
var option= obj1.options[i];
//引用软件被选中项不加入
if(i!=obj1.selectedIndex){
//克隆OPTION并添加到SELECT中
obj2.appendChild(option.cloneNode(true));
}
}
}
##HTML code:
<TABLE width="100%" border=0 align="left" cellPadding=0 cellSpacing=1> <tr> <td class="Search_item_18"> <span class="Edit_mustinput">*</span>引用软件：</td> <td class="Search_content_82"> <input name="yyrjMc" id="yyrjMc" type="text" class="Search_input" tabindex="3" size="30" > <input name="yyrjDm" id="yyrjDm" type="hidden" > <input type="button" class="Search_button_select" onClick="linkAgeTree('linkage','yyrjtree','yyrjMc','yyrjDm','linkageTree','1');" value="选择..."> </td> </tr> <tr> <td class="Search_item"> <span class="Edit_mustinput">*</span>引用分版：</td> <td class="Search_content" id="yyfb"> <select name="yyfbDm" style="width:160" id="yyfbDm" onChange="getCpgjThgl('yyfbDm','thgjDm')"> </select> </td> </tr> <tr> <td class="Search_item">退化构件：</td> <td class="Search_content" id="thgj"> <select name="thgjDm" style="width:160" id="thgjDm"> <option value="-1" selected>无</option> </select> </td> </tr> </TABLE>
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