Updating properties in the code-behind from JavaScript

Question

Updating properties in the code-behind from JavaScript

I have a JavaScript function called Func() within my user control that updates the value of a hidden field. I am looking to also assign this hidden field value to a code-behind property in the same JavaScript function so that it can be accessed in the parent ASPX.VB page without requiring a postback.

<script type="text/javascript" >

    function func(id) {

        HFTargetSign = id;
        alert(HFTargetSign);
    }
</script>

Does anyone have suggestions on how to successfully implement this?

javascript asp.net

Answer 1

Answer №1

If you're looking to transfer values from the code behind to JavaScript, there are two main methods you can use:

Utilizing hidden fields

Or working with Protected type variables

public partial class _Default : System.Web.UI.Page
{
    protected string Variable_codebehind;
    protected void Page_Load(object sender, EventArgs e)
    {
        Variable_codebehind = "Something";
    }
}

<html xmlns="http://www.w3.org/1999/xhtml">  
    <head runat="server"> 
    <title>Ashish's Blog</title>
      <script type="text/javascript">
             ////Retrieving variable from ASP.NET code behind  
              alert("<%=Variable_codebehind %>");
       </script>
    </head>
    <body>
    <form id="form1" runat="server">  
    <div>  
    </div>  
    </form>  
    </body>
</html>

Another Option:

It's possible that if your hidden field is a server control, the ID may be generated as something different from filesPercentage (perhaps something like ctl00_ctl00_filesPercentage)
You might need to utilize the generated client ID in your JavaScript
```
document.getElementById("<%=filesPercentage.ClientID%>").value;
```
Or explore other ways to access the hidden value, such as $('[hidden's parent element] input[type="hidden"]').val()

Answer 2

If you're looking to transfer values from the code behind to JavaScript, there are two main methods you can use:

Utilizing hidden fields

Or working with Protected type variables

public partial class _Default : System.Web.UI.Page
{
    protected string Variable_codebehind;
    protected void Page_Load(object sender, EventArgs e)
    {
        Variable_codebehind = "Something";
    }
}

<html xmlns="http://www.w3.org/1999/xhtml">  
    <head runat="server"> 
    <title>Ashish's Blog</title>
      <script type="text/javascript">
             ////Retrieving variable from ASP.NET code behind  
              alert("<%=Variable_codebehind %>");
       </script>
    </head>
    <body>
    <form id="form1" runat="server">  
    <div>  
    </div>  
    </form>  
    </body>
</html>

Another Option:

It's possible that if your hidden field is a server control, the ID may be generated as something different from filesPercentage (perhaps something like ctl00_ctl00_filesPercentage)
You might need to utilize the generated client ID in your JavaScript
```
document.getElementById("<%=filesPercentage.ClientID%>").value;
```
Or explore other ways to access the hidden value, such as $('[hidden's parent element] input[type="hidden"]').val()

Updating properties in the code-behind from JavaScript

Answer №1

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