使用javascript更改后获取文本框值 [英] Get textbox value after changing with javascript

问题描述

通过下拉列表中的javascript更改文本框的值更改（无回发）。文本框正确更新，但提交表单时未提供值。我认为这是因为javascript更改只发生在客户端？如何在服务器端获得此值？



我尝试过：

< pre> < script type =text / javascript> 
 function ddlChange（）{
 var ddl = document.getElementById（'<％= DDLg4corp.ClientID％>'）; 
 var textBox = document.getElementById（'<％= txtg4action.ClientID％>'）; 
 
 textBox.value = ddl.options [ddl.selectedIndex] .value; 
} 
< / script> 
 
< asp：DropDownList runat =serverID =DDLg4corponchange =ddlChange（）;> 
< asp：ListItem Value =1Text =Option 1>< / asp：ListItem> 
< asp：ListItem Value =2Text =Option 2>< / asp：ListItem> 
< asp：ListItem Value =3Text =Option 3>< / asp：ListItem> 
< asp：ListItem Value =4Text =Option 4>< / asp：ListItem> 
< / asp：DropDownList> 
 
< asp：TextBox runat =serverid =txtg4action>< / asp：TextBox> 

 Private Sub Button_Click（发件人为对象，e为EventArgs）处理btnSubmit1.Click，
 
 
更新
 .Connection = connection 
 .CommandType = CommandType.Text 
如果qrtSelect.SelectedValue = 1则
 .CommandText =更新表集txtg4action = @ txtg4action其中users = @ users
 .Parameters.AddWithValue（@ txtg4action，txtg4action.Text）

解决方案

< blockquote>嗯，正如所承诺的，这是一个使用你的代码的简单页面：

 <％@  < span class =code-attribute>   Page    语言  =  VB   ％>  
 <   script     runat   =  server >  
 私有  Sub  btnGo_Click（ ByVal 发​​件人 As  对象， ByVal  e  As  EventArgs ）
 litX.Text =  您选择了& txtg4action.Text 
 结束  Sub  
 < /   script  >  
 <   html  >  
 <   head  >  
 <   title  >  <   / title  >  
 <   script     type   =  text / javascript >  
  function  ddlChange（）{
  var  ddl =  document  .getElementById（' <％= DDList.ClientID％>'）; 
  var  textBox =  document  .getElementById（'  <％= txtg4action.ClientID％>'）; 
 textBox.value = ddl.options [ddl.selectedIndex] .value; 
} 
 <   /  脚本 >  
 <   / head  >  
 <   body  >  
 <  表单    id   =   Form1    runat  < span class =code-keyword> =  server >  
 <   p  >  <   asp：DropDownList    < span class =code-attribute> runat   =  server    ID   =  DDList    onchange   =  ddlChange（）; >  
 <   asp：ListItem     Value   =  1   < span class =code-attribute>文本  = 选项1 >  <   / asp：ListItem  >  
 <   asp：ListItem    值  =  2   文字  = 选项2 >  <   / asp：ListItem  >  
 <   asp：ListItem    值  =  3   文字  =  选项3 >  <   / asp：ListItem  >  
 <   asp：ListItem     Value   =  4   < span class =code-attribute>文本  = 选项4 >  <   / asp：ListItem  >  
 <   / a sp：DropDownList  >  <   / p  >  
 <   p  >  <   asp： TextBox     runat   =  server    id   =  txtg4action >  <   / asp：TextBox  >  <   / p  >  
 <   p  >  <   asp：按钮    runat   =  server    ID   =  btnGo    OnClick   =  btnGo_Click   文字  = 提交    /  >  <   / p  >  
 <   p  >  <   asp：Literal     runat   =   server    id  < span class =code-keyword> =  litX    /  >  <   / p  >  
 <   / form  >  
 <   / body  >  
 <   / html  >  

Changing the value of a textbox via javascript on dropdownlist change (no postback). Textbox updates properly but the value does not come through when the form is submitted. I assume this is because the javascript change is only happening on the client side? How can I get this value on server side?

What I have tried:

<pre>  <script type="text/javascript">
      function ddlChange() {
          var ddl = document.getElementById('<%=DDLg4corp.ClientID %>');
          var textBox = document.getElementById('<%= txtg4action.ClientID%>');

          textBox.value = ddl.options[ddl.selectedIndex].value;
      }
</script>

<asp:DropDownList runat="server" ID="DDLg4corp" onchange="ddlChange();">
  <asp:ListItem Value="1" Text="Option 1"></asp:ListItem>
  <asp:ListItem Value="2" Text="Option 2"></asp:ListItem>
  <asp:ListItem Value="3" Text="Option 3"></asp:ListItem>
  <asp:ListItem Value="4" Text="Option 4"></asp:ListItem>
</asp:DropDownList>

<asp:TextBox runat="server" id="txtg4action"></asp:TextBox> 

 Private Sub Button_Click(sender As Object, e As EventArgs) Handles btnSubmit1.Click,


With update
  .Connection = connection
  .CommandType = CommandType.Text
    If qrtSelect.SelectedValue = 1 Then
       .CommandText = "Update table set txtg4action=@txtg4action where users=@users"
       .Parameters.AddWithValue("@txtg4action", txtg4action.Text)

解决方案

Well, as promised, here's a simple page using your code:

<%@ Page Language="VB" %>
<script runat="server"> 
    Private Sub btnGo_Click(ByVal Sender As Object, ByVal e As EventArgs)
      litX.Text = "You selected " & txtg4action.Text
    End Sub
</script>
<html>
<head>
   <title></title> 
   <script type="text/javascript">
      function ddlChange() {
         var ddl = document.getElementById('<%=DDList.ClientID %>');
            var textBox = document.getElementById('<%= txtg4action.ClientID%>');
            textBox.value = ddl.options[ddl.selectedIndex].value;
         }
   </script>
</head>
<body>
    <form id="Form1" runat="server"> 	   
      <p><asp:DropDownList runat="server" ID="DDList" onchange="ddlChange();">
        <asp:ListItem Value="1" Text="Option 1"></asp:ListItem>
        <asp:ListItem Value="2" Text="Option 2"></asp:ListItem>
        <asp:ListItem Value="3" Text="Option 3"></asp:ListItem>
        <asp:ListItem Value="4" Text="Option 4"></asp:ListItem>
      </asp:DropDownList></p>
      <p><asp:TextBox runat="server" id="txtg4action"></asp:TextBox></p>  
      <p><asp:Button runat="server" ID="btnGo" OnClick="btnGo_Click" Text="Submit" /></p>
	  <p><asp:Literal runat="server" id="litX" /></p>	
    </form>
</body>
</html>

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