ClientScriptManager.RegisterStartupScript Method (Type, String, String, Boolean)

 

Registers the startup script with the Page object using a type, a key, a script literal, and a Boolean value indicating whether to add script tags.

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

Public Sub RegisterStartupScript (
	type As Type,
	key As String,
	script As String,
	addScriptTags As Boolean
)

Parameters

type
Type: System.Type

The type of the startup script to register.

key
Type: System.String

The key of the startup script to register.

script
Type: System.String

The startup script literal to register.

addScriptTags
Type: System.Boolean

A Boolean value indicating whether to add script tags.

Exception Condition
ArgumentNullException

type is null.

A startup script is uniquely identified by its key and its type. Scripts with the same key and type are considered duplicates. Only one script with a given type and key pair can be registered with the page. Attempting to register a script that is already registered does not create a duplicate of the script.

Call the IsStartupScriptRegistered method to determine whether a startup script with a given key and type pair is already registered and avoid unnecessarily attempting to add the script.

In this overload of the RegisterStartupScript method, you can indicate whether the script provided in the script parameter is wrapped with a <script> element block by using the addScriptTags parameter. Setting addScriptTags to true indicates that script tags will be added automatically.

The script block added by the RegisterStartupScript method executes when the page finishes loading but before the page's OnLoad event is raised. The script blocks are not guaranteed to be output in the order they are registered. If the order of the script blocks is important, use a StringBuilder object to gather the scripts together in a single string, and then register them all in a single client script block.

The following code example demonstrates the use of the RegisterStartupScript method. Note that the addScriptTags parameter is set to false so the beginning and closing script tags are included with the script parameter.

<%@ 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 System.EventArgs)

    ' Define the name and type of the client scripts on the page.
    Dim csname1 As String = "PopupScript"
    Dim csname2 As String = "ButtonClickScript"
    Dim cstype As Type = Me.GetType()

    ' Get a ClientScriptManager reference from the Page class.
    Dim cs As ClientScriptManager = Page.ClientScript

    ' Check to see if the startup script is already registered.
    If (Not cs.IsStartupScriptRegistered(cstype, csname1)) Then

      Dim cstext1 As String = "alert('Hello World');"
      cs.RegisterStartupScript(cstype, csname1, cstext1, True)

    End If

    ' Check to see if the client script is already registered.
    If (Not cs.IsClientScriptBlockRegistered(cstype, 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>")
      cs.RegisterClientScriptBlock(cstype, csname2, cstext2.ToString(), False)

    End If

  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ClientScriptManager 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 2.0
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