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Page.IsClientScriptBlockRegistered Method

NOTE: This API is now obsolete.

Determines whether the client script block with the specified key is registered with the page.

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

[ObsoleteAttribute("The recommended alternative is ClientScript.IsClientScriptBlockRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202")]
public bool IsClientScriptBlockRegistered(
	string key


Type: System.String

The string key of the client script to search for.

Return Value

Type: System.Boolean
true if the script block is registered; otherwise, false.

Call this method before calling Page.RegisterClientScriptBlock to avoid unnecessarily assembling the client-side script. This is particularly important if the script requires a large amount of server resources to create.

The IsClientScriptBlockRegistered method has been deprecated. Use the IsClientScriptBlockRegistered method in the ClientScriptManager class.

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