Page.IsClientScriptBlockRegistered Method (String)
Determines whether the client script block with the specified key is registered with the page.
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.
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>
Available since 1.1