js 操做select和option，添加select列

時間 2019-12-11

原文原文鏈接

1.動態建立selectjavascript

function createSelect(){html

var mySelect = document.createElement("select");
          mySelect.id = "mySelect";
          document.body.appendChild(mySelect);
      }java

2.添加選項option數組

function addOption(){app

//根據id查找對象，
var obj=document.getElementById('mySelect');post

           //添加一個選項
obj.add(new Option("文本","值"));    //這個只能在IE中有效
         obj.options.add(new Option("text","value")); //這個兼容IE與firefox
     }ui

3.刪除全部選項optionthis

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

}firefox

4.刪除一個選項option

function removeOne(){
var obj=document.getElementById('mySelect');

//index,要刪除選項的序號，這裏取當前選中選項的序號

var index=obj.selectedIndex;
obj.options.remove(index);
}

5.得到選項option的值

var obj=document.getElementById('mySelect');

var index=obj.selectedIndex; //序號，取當前選中選項的序號

var val = obj.options[index].value;

6.得到選項option的文本

var obj=document.getElementById('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.getElementById('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.getElementById("mySelect");
mySelect.parentNode.removeChild(mySelect);
     }

9.設置selected

obj.options[1].selected=true

整個實例的完整代碼以下：

<!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("浦東新區","101"))
      sh.add(new Option("黃浦區","102"))
      sh.add(new Option("徐彙區","103"))
      sh.add(new Option("普陀區","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("玄武區","201"))
      nj.add(new Option("白下區","202"))
      nj.add(new Option("下關區","203"))
      nj.add(new Option("棲霞區","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>
<div id="context">
   <select id="area" onchange="choice()">
   </select>
</div>
<input type=button value="顯示" onclick="show()">
<input type=button value="計算結點" onclick="calc()">
<input type=button value="刪除" onclick="remove()">
</body>
</html>

改進版：在select中添加、修改、刪除option元素

整個實例的完整代碼以下：

<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title>javascript select options text value</title>
<meta name="keywords" content="javascript select options text value add modify delete set">
<meta name="description" content="javascript select options text value add modify delete set">
<script language="javascript">

</script>
</head>
<body>
<form name="watch" method="post" action="">
<select id="MySelect" name="keywords" size="10" onchange="watch_sel(this.form)"></select><br>
<script language="javascript">

</script>
<input type="text" name="word" /><br />
<input type="button" value="增長" onclick="watch_add(this.form);" />
<input type="button" value="修改" onclick="watch_mod(this.form);" />
<input type="button" value="刪除" onclick="watch_del(this.form);" />
<input type="button" value="保存" onclick="watch_set(this.form);" />
</form>

用一個字符串建立一個數組方法:

</body>
</html>
<script>
function spli(){
datastr="2,2,3,5,6,6";
var str= new Array();
str=datastr.split(",");
for (i=0;i<str.length ;i++ )
{ document.write(str[i]+"<br/>"); }
}
spli();
</script>

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