Page.IsClientScriptBlockRegistered Method (String)

 
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 Function IsClientScriptBlockRegistered (
	key As String
) As Boolean

Parameters

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.

<%@ Page Language="VB"  %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<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.'} </")
            cstext2.Append("script>")
            RegisterClientScriptBlock(csname2, cstext2.ToString())
        End If
    End Sub
</script>
<html  >
  <head>
    <title>RegisterClientScriptBlock Example</title>
  </head>
  <body>
     <form id="Form1"
         runat="server">
        <input type="text" id="Message" /> <input type="button" value="ClickMe" onclick="DoClick()" />
     </form>
  </body>
</html>

.NET Framework
Available since 1.1
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