How to: Add Client Script Dynamically to ASP.NET Web Pages

How to: Add Client Script Dynamical...

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Microsoft Visual Studio 2008/.NET Framework 3.5

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ASP.NET

How to: Add Client Script Dynamically to ASP.NET Web Pages

Using server code, you can add client script to a page. Creating client script in server code is useful when the contents of the client script depend on information that is not available until run time. Adding client script to the page dynamically is also useful when you want the client script to execute in the following situations:

When the page has finished loading

When users submit the page

Note:
You can also add client events, such as onmouseover and onkeyup, to individual controls. For details, see How to: Add Client Script Events to ASP.NET Web Server Controls.

To add client script to an ASP.NET Web page dynamically

In server code, call one of the methods listed in the following table.

Method	Description
RegisterClientScriptBlock	Adds a script block to the top of the page. You create the script as a string, and then pass it to the method, which adds it to the page. You can use this method to insert any script into the page. Note that the script might be rendered into the page before all the elements are finished; therefore, you might not be able to reference all the elements on the page from the script.
RegisterClientScriptInclude	Similar to the RegisterClientScriptBlock method, but adds a script block that references an external .js file. The include file is added before any other dynamically added script; therefore, you might not be able to reference some elements on the page.
RegisterStartupScript	Adds a script block into the page that executes when the page finishes loading but before the page's onload event is raised. The script is typically not created as an event handler or function; it generally includes only the statements you want to execute once.
RegisterOnSubmitStatement	Adds script that executes in response to the page's onsubmit event. The script is executed before the page is submitted, and gives you an opportunity to cancel the submission.

The following code example shows how to add client script to a page that executes when the user clicks a button that posts the page back to the server. The client script displays a pop-up window requesting the user to confirm the postback.

Visual Basic

Protected Sub Page_Load(ByVal sender As Object, _
        ByVal e As System.EventArgs)
    Dim scriptText As String
    scriptText = "return confirm('Do you want to submit the page?')"
    ClientScript.RegisterOnSubmitStatement(Me.GetType(), _
        "ConfirmSubmit", scriptText)
End Sub

protected void Page_Load(Object sender, EventArgs e)
{
    String scriptText = 
        "return confirm('Do you want to submit the page?')";
    ClientScript.RegisterOnSubmitStatement(this.GetType(), 
        "ConfirmSubmit", scriptText);
}

Tasks

How to: Add Client Script Events to ASP.NET Web Server Controls

Concepts

Client Script in ASP.NET Web Pages

Implementing Client Callbacks Programmatically Without Postbacks in ASP.NET Web Pages