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Page.RegisterClientScriptBlock Method

NOTE: This API is now obsolete.

Emits client-side script blocks to the response.

Namespace:  System.Web.UI
Assembly:  System.Web (in System.Web.dll)

[ObsoleteAttribute("The recommended alternative is ClientScript.RegisterClientScriptBlock(Type type, string key, string script). http://go.microsoft.com/fwlink/?linkid=14202")]
public virtual void RegisterClientScriptBlock(
	string key,
	string script


Type: System.String

Unique key that identifies a script block.

Type: System.String

Content of script that is sent to the client.

The client-side script is emitted just after the opening tag of the Page object's <form runat= server> element. Be sure to include opening and closing <script> elements around the script block string specified in the script parameter.

Because this method uses a key to identify the script block, the script block does not have to be emitted to the output stream each time it is requested by a different server control instance. Using a key also decreases the likelihood of different controls' script blocks interfering with each other.

Any script blocks with the same key parameter values are considered duplicates.


Remember to include HTML comment tags around your script so that it will not be rendered if the requesting browser does not support scripts.

The RegisterClientScriptBlock method has been deprecated. Use the RegisterClientScriptBlock method in the ClientScriptManager class instead.

The following code example demonstrates the use of the RegisterClientScriptBlock method in conjunction with the IsClientScriptBlockRegistered method. If the ECMAScript in the code declaration block has not already been registered, as determined by IsClientScriptBlockRegistered, the RegisterClientScriptBlock call is made.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
<html xmlns="http://www.w3.org/1999/xhtml" >
    <title>ASP.NET Example</title>
<script language="C#" runat="server">

      public void Page_Load(Object sender, EventArgs e)

        if (!this.IsClientScriptBlockRegistered("clientScript"))
          // Form the script that is to be registered at client side.
          String scriptString = "<script language=\"JavaScript\"> function DoClick() {";
          scriptString += "myForm.show.value='Welcome to Microsoft .NET'}<";
          scriptString += "/";
          scriptString += "script>";
          this.RegisterClientScriptBlock("clientScript", scriptString);

  <body style="margin-top:20; margin-left:10">
     <form id="myForm" runat="server">
        <input type="text" id="show" style="width:200" /> <input type="button" value="ClickMe" onclick="DoClick()" />

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 1.1, 1.0
Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 3.5 SP1
Obsolete (compiler warning) in 3.0
Obsolete (compiler warning) in 3.0 SP1
Obsolete (compiler warning) in 3.0 SP2
Obsolete (compiler warning) in 2.0
Obsolete (compiler warning) in 2.0 SP1
Obsolete (compiler warning) in 2.0 SP2

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