RegisterStartupScript Method
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Page.RegisterStartupScript Method (String, String)

Note: This API is now obsolete.

Emits a client-side script block in the page response.

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

[ObsoleteAttribute("The recommended alternative is ClientScript.RegisterStartupScript(Type type, string key, string script).")]
public virtual void RegisterStartupScript(
	string key,
	string script


Type: System.String

Unique key that identifies a script block.

Type: System.String

Content of script that will be sent to the client.

Similar to the RegisterClientScriptBlock method, the RegisterStartupScript method emits the script just before the closing tag of the Page object's <form runat= server> element. Be sure to include opening and closing <script> elements around the script block string specified in the script parameter.

Because this method uses a key to identify the script block, the script block does not have to be emitted to the output stream each time it is requested by a different server control instance

Any script blocks with the same key parameter values are considered duplicates.


Remember to include HTML comment tags around your script so that it will not be rendered if the requesting browser does not support scripts.

The RegisterStartupScript method has been deprecated. Use the RegisterStartupScript method in the ClientScriptManager class instead.

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 the IsStartupScriptRegistered method, then a RegisterStartupScript call is made.

<%@ Page Language="C#"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<script runat="server">
  public void Page_Load(Object sender, EventArgs e)
    String csname1 = "PopupScript";
    String csname2 = "ButtonClickScript";

    if (!IsClientScriptBlockRegistered(csname1))
        String cstext1 = "<script type=\"text/javascript\">" +
            "alert('Hello World');</" + "script>";
        RegisterStartupScript(csname1, cstext1);

    if (!IsClientScriptBlockRegistered(csname2))
      StringBuilder cstext2 = new StringBuilder();
      cstext2.Append("<script type=\"text/javascript\"> function DoClick() {");
      cstext2.Append("Form1.Message.value='Text from client script.'} </");
      RegisterClientScriptBlock(csname2, cstext2.ToString());
<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
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