js将input files清空 js清空option

转载

mob64ca13f8eecb 2024-04-29 09:34:51

文章标签 js将input files清空 javascript xhtml ViewUI html 文章分类 架构后端开发

1.动态创建select

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

2.添加选项option

function addOption(){
          //根据id查找对象，
           var obj=document.getElementById('mySelect');           //添加一个选项
obj.add(new Option("文本","值"));    //这个只能在IE中有效
         obj.options.add(new Option("text","value")); //这个兼容IE与firefox
     }

3.删除所有选项option

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

4.删除一个选项option

function removeOne(){
           var obj=document.getElementById('mySelect');           //index,要删除选项的序号，这里取当前选中选项的序号
var index=obj.selectedIndex;
obj.options.remove(index);
     }

5.获得选项option的值

var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val = obj.options[index].value;

6.获得选项option的文本

var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val = obj.options[index].text;

7.修改选项option

var obj=document.getElementById('mySelect');
var index=obj.selectedIndex; //序号，取当前选中选项的序号
var val = obj.options[index]=new Option("新文本","新值");

8.删除select

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

整个实例的完整代码如下：

<!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>
<div id="context">
   <select id="area" οnchange="choice()">
   </select>
</div>
<input type=button value="显示" οnclick="show()">
<input type=button value="计算结点" οnclick="calc()">
<input type=button value="删除" οnclick="remove()">
</body>
</html>

改进版：在select中添加、修改、删除option元素

function watch_ini(){ // 初始
for(var i=0; i<arguments.length; i++){
var word = document.createElement("OPTION");
word.text = arguments[i];
watch.keywords.add(word); // watch. is form name
}
}
function watch_add(f){ // 增加
var word = document.createElement("OPTION");
word.text = f.word.value;
f.keywords.add(word);
}
但上述 add() 方法只在IE下有效，为兼容FF和Opera，对上述代码进行了一下改进，改动后代码如下： function watch_ini(){ // 初始
for(var i=0; i<arguments.length; i++){
   var oOption=new Option(arguments[i],arguments[i]);
   document.getElementById("MySelect")[i]=oOption;
}
}
function watch_add(f){ // 增加
   var oOption=new Option(f.word.value,f.word.value);
   f.keywords[f.keywords.length]=oOption;
}

整个实例的完整代码如下：

<!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">
<!--
function watch_ini(){ // 初始
for(var i=0; i<arguments.length; i++){
   var oOption=new Option(arguments[i],arguments[i]);
   document.getElementById("MySelect")[i]=oOption;
}
}
function watch_add(f){ // 增加
   var oOption=new Option(f.word.value,f.word.value);
   f.keywords[f.keywords.length]=oOption;
}
function watch_sel(f){ // 编辑
f.word.value = f.keywords[f.keywords.selectedIndex].text;
}
function watch_mod(f){ // 修改
f.keywords[f.keywords.selectedIndex].text = f.word.value;
}
function watch_del(f){ // 删除
f.keywords.remove(f.keywords.selectedIndex);
}
function watch_set(f){ // 保存
var set = "";
for(var i=0; i<f.keywords.length; i++){
set += f.keywords[i].text + ";";
}
confirm(set);
}
//-->
</script>
</head>
<body>
<form name="watch" method="post" action="">
<select id="MySelect" name="keywords" size="10" οnchange="watch_sel(this.form)"></select><br>
<script language="javascript">
<!--
watch_ini("我","你","妳","他","她","它","尔"); // 初始关键词
//-->
</script>
<input type="text" name="word" /><br />
<input type="button" value="增加" οnclick="watch_add(this.form);" />
<input type="button" value="修改" οnclick="watch_mod(this.form);" />
<input type="button" value="删除" οnclick="watch_del(this.form);" />
<input type="button" value="保存" οnclick="watch_set(this.form);" />
</form>

用一个字符串创建一个数组方法:

<script language="javascript">   
 </body>
</html> <script>functionspli(){datastr="2,2,3,5,6,6";      varstr=newArray();       str=datastr.split(",");          for(i=0;i<str.length ;i++ )        {document.write(str[i]+"<br/>");  }   }   spli();   </script>

二

<select id="ddlResourceType" οnchange="getvalue(this)">
</select>

动态删除select中的所有options：

document.getElementById("ddlResourceType").options.length=0;

动态删除select中的某一项option：

document.getElementById("ddlResourceType").options.remove(indx);

动态添加select中的项option:

document.getElementById("ddlResourceType").options.add(new Option(text,value));

上面在IE和FireFox都能测试成功，希望以后你可以用上。

其实用标准的DOM操作也可以，就是document.createElement，appendChild，removeChild之类的。

取值方面

function getvalue(obj)
    {
        var m=obj.options[obj.selectedIndex].value
        alert(m);//获取value
        var n=obj.options[obj.selectedIndex].text
        alert(n);//获取文本
    }

==============================================================================

1 检测是否有选中

if (objSelect.selectedIndex > - 1 ) {
// 说明选中
} else {
// 说明没有选中
}

2 删除被选中的项

objSelect.options[objSelect.selectedIndex] = null ;

3 增加项

objSelect.options[objSelect.length] = new Option( " 你好 " , " hello " );

4 修改所选择中的项

objSelect.options[objSelect.selectedIndex] = new Option( " 你好 " , " hello " );

5 得到所选择项的文本

objSelect.options[objSelect.selectedIndex].text;

6 得到所选择项的值

objSelect.options[objSelect.selectedIndex].value;
======================================================================
<%@LANGUAGE="VBSCRIPT" CODEPAGE="936"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>JS对select动态添加options操作[IE和FireFox兼容]</title>
<script language="javascript" type="text/javascript">
function xlbchange(s){
switch (s){
   case "1" :
       document.getElementById("lb").options.length=0;
     var soojs_value=[0,1,2,3];
    var soojs_text=["精神提炼","作风设计","目标设置","理念提升"];
    for ( var i=0;i<soojs_value.length;i++){
     var   oOption   =   document.createElement("OPTION");  
     oOption.value=soojs_value[i];  
     oOption.text=soojs_text[i];  
     zpmange.lb.options.add(oOption);
     }
      break;
   case "2" :
       document.getElementById("lb").options.length=0;
     var soojs_value=[0,1,2,3,4,5,6,7];
    var soojs_text=["校徽","校训","校歌","校名字体","校史展室","宣传画册","宣传光盘","办公用品纪念品"];
    for ( var i=0;i<soojs_value.length;i++){
     var   oOption   =   document.createElement("OPTION");  
     oOption.value=soojs_value[i];  
     oOption.text=soojs_text[i];  
     zpmange.lb.options.add(oOption);
     }  
      break;
        case "3":
    document.getElementById("lb").options.length=0;
     var soojs_value=[0,1,2,3];
    var soojs_text=["校园景观设计","校园雕塑设计","校园浮雕设计","走廊文化设计"];
    for ( var i=0;i<soojs_value.length;i++){
     var   oOption   =   document.createElement("OPTION");  
     oOption.value=soojs_value[i];  
     oOption.text=soojs_text[i];  
     zpmange.lb.options.add(oOption);
     }
   break;   
        case "4":
    document.getElementById("lb").options.length=0;
     var soojs_value=[0,1,2];
    var soojs_text=["学校制度","文化活动","行为规范"];
    for ( var i=0;i<soojs_value.length;i++){
     var   oOption   =   document.createElement("OPTION");  
     oOption.value=soojs_value[i];  
     oOption.text=soojs_text[i];  
     zpmange.lb.options.add(oOption);
     }
   break;
default :
   document.getElementById("lb").options.length=0;
var   oOption   =   document.createElement("OPTION");
     oOption.value=0;  
     oOption.text="请选择作品类别";
zpmange.lb.options.add(oOption);
}
}
</script>
</head>
<body>
<form action="zpmange.asp" name="zpmange" method="post">
<p><select id="ddlResourceType" οnchange="getvalue(this)"><br />
</select></p>
<p> 动态删除select中的所有options： <br />
    document.getElementById("ddlResourceType").options.length=0; <br />
<br />
    动态删除select中的某一项option： <br />
    document.getElementById("ddlResourceType").options.remove(indx); </p>
<p> 动态添加select中的项option: <br />
    document.getElementById("ddlResourceType").options.add(new Option(text,value)); </p>
<p> 上面在IE和FireFox都能测试成功，希望以后你可以用上。 <br />
    其实用标准的DOM操作也可以，就是document.createElement，appendChild，removeChild之类的。 </p>
<p>取值方面<br />
    function getvalue(obj)<br />
    {<br />
    var m=obj.options[obj.selectedIndex].value<br />
    alert(m);//获取value<br />
    var n=obj.options[obj.selectedIndex].text<br />
    alert(n);//获取文本<br />
    }<br />
</p>
<p>例子：</p>
<table width="80%" border="0" align="center" cellpadding="1" cellspacing="1" style="border-style:double">
    <tr>
      <td width="50%" height="41" ><div align="center">
      
            <select name="xt" id="xt" οnchange="xlbchange(this.value)">
          <option selected="selected">请选择作品系统</option>
                  <option value="1">理念视别系统</option>
                  <option value="2">视觉识别系统</option>
                  <option value="3">环境视别系统</option>
                  <option value="4">行为视别系统</option>         
        </select>
               
      </div></td>
      <td width="61%" ><div align="center">
        <select name="lb" id="lb">
   <option selected="selected">请选择作品类别</option>
        </select>
      </div></td>
    </tr>
    <tr>
      <td height="203" colspan="2" > </td>
    </tr>
</table>
</form>
</body>
</html>

本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。