IsStartupScriptRegistered Method
Collapse the table of content
Expand the table of content

Page.IsStartupScriptRegistered Method (String)

Note: This API is now obsolete.

Determines whether the client startup script is registered with the Page object.

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

<ObsoleteAttribute("The recommended alternative is ClientScript.IsStartupScriptRegistered(string key).")>
Public Function IsStartupScriptRegistered (
	key As String
) As Boolean


Type: System.String

The string key of the startup script to search for.

Return Value

Type: System.Boolean

true if the startup script is registered; otherwise, false.

Call this method before calling Page.RegisterStartupScript 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 IsStartupScriptRegistered method has been deprecated. Use the IsStartupScriptRegistered method in the ClientScriptManager class.

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

<%@ Page Language="VB"  %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<script runat="server">
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim csname1 As String = "PopupScript"

        Dim csname2 As String = "ButtonClickScript"

        If Not IsClientScriptBlockRegistered(csname1) Then
            Dim cstext1 As String = "<script type=""text/javascript"">" & _
                "alert('Hello World');</" & "script>"
            RegisterStartupScript(csname1, cstext1)
        End If

        If Not IsClientScriptBlockRegistered(csname2) Then
            Dim cstext2 As New StringBuilder()
            cstext2.Append("<script type=""text/javascript""> function DoClick() {")
            cstext2.Append("Form1.Message.value='Text from client script.'} </")
            RegisterClientScriptBlock(csname2, cstext2.ToString())
        End If
    End Sub
<html  >
    <title>RegisterClientScriptBlock Example</title>
     <form id="Form1"
        <input type="text" id="Message" /> <input type="button" value="ClickMe" onclick="DoClick()" />

.NET Framework
Available since 1.1
Return to top
© 2015 Microsoft