HTML select option detailed description-HTML Tutorial-php.cn

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
< ;option>My bag

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>

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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,&#39;0&#39;);   
var tempOption=null;
for(var i=0;i<nodeArray.length;i++){
//create select Option
tempOption= $j(&#39;<option value="&#39;+nodeArray[i].dm+&#39;">&#39;+nodeArray[i].mc+&#39;</option> &#39;);
//put Option to select
tempSelect.append(tempOption);
}
// 获取退化构件列表
getCpgjThgl(selectId,&#39;thgjDm&#39;);
}
/**
* @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,&#39;1&#39;);
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));
}
}
}

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##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(&#39;linkage&#39;,&#39;yyrjtree&#39;,&#39;yyrjMc&#39;,&#39;yyrjDm&#39;,&#39;linkageTree&#39;,&#39;1&#39;);" 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(&#39;yyfbDm&#39;,&#39;thgjDm&#39;)">

</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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