可输入的DropDownList控件

 1 <% @ Page language="c#" Codebehind="ddlWriteControl.aspx.cs" AutoEventWireup="false" Inherits="WebDemo.ddlWriteControl"  %>
 2 <! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"  >
 3 < HTML >
 4      < HEAD >
 5          < title > ddlWriteControl </ title >
 6          < meta  name ="GENERATOR"  Content ="Microsoft Visual Studio .NET 7.1" >
 7          < meta  name ="CODE_LANGUAGE"  Content ="C#" >
 8          < meta  name ="vs_defaultClientScript"  content ="JavaScript" >
 9          < meta  name ="vs_targetSchema"  content ="http://schemas.microsoft.com/intellisense/ie5" >
10          < style >  #div1 {}{ Z-INDEX: 1; LEFT: 250px; WIDTH: 216px; CLIP: rect(3px 280px 21px 110px); POSITION: absolute; TOP: 89px; HEIGHT: 72px } #div2 {}{ LEFT: 250px; WIDTH: 95px; POSITION: absolute; TOP: 89px; HEIGHT: 18px; 2: }  </ style >
11      </ HEAD >
12      < body  MS_POSITIONING ="GridLayout" >
13          < script  language ="javascript" >
14        function AddOption()
15        {    
16            var val = document.getElementById("txtValue").value;
17            var option = document.getElementById("ddl");
18            
19            if(val == "")
20            {
21                alert("请输入项值");
22                return;
23            }
24            if(option.length > 0)
25            {
26                for(var i=0;i<option.length;i++)
27                {
28                    if(option.options[i].value == val)
29                    {
30                        alert("该值已存在！");
31                        return;
32                    }
33                }
34            }
35            
36            var option_val = new Option(val,val);
37                        
38            option.add(option_val);
39            option.selectedIndex = option.options.length-1;
40            
41        }
42         </ script >
43          < form  id ="Form1"  method ="post"  runat ="server" >
44              < div  id ="div1"  style ="Z-INDEX: 101; WIDTH: 128px; HEIGHT: 72px" >                 
45                  < asp:DropDownList  id ="ddl"  onchange ="document.getElementById('txtValue').value = this.value"  runat ="server"
46                     Width ="127" >
47                      < asp:ListItem  Value ="aaa1" > aaa1 </ asp:ListItem >
48                      < asp:ListItem  Value ="bbb2" > bbb2 </ asp:ListItem >
49                      < asp:ListItem  Value ="ccc3" > ccc3 </ asp:ListItem >
50                  </ asp:DropDownList >
51              </ div >
52              < FONT  face ="宋体" ></ FONT >
53              < div  id ="div2" >                 
54                  < asp:TextBox  id ="txtValue"  style ="PADDING-LEFT:2px;PADDING-TOP:2px"  runat ="server"  Width ="127" ></ asp:TextBox >
55                  < input  type ="button"  value ="OK"  id ="btn"  onclick ="AddOption();" >
56              </ div >
57             
58          </ form >
59      </ body >
60 </ HTML >
61

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