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Page.IsStartupScriptRegistered(String) Method

  • Reference

Definition

Namespace:
System.Web.UI
Assembly:
System.Web.dll

Caution

The recommended alternative is ClientScript.IsStartupScriptRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202

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

public:
 bool IsStartupScriptRegistered(System::String ^ key);
public bool IsStartupScriptRegistered (string key);
[System.Obsolete("The recommended alternative is ClientScript.IsStartupScriptRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202")]
public bool IsStartupScriptRegistered (string key);
member this.IsStartupScriptRegistered : string -> bool
[<System.Obsolete("The recommended alternative is ClientScript.IsStartupScriptRegistered(string key). http://go.microsoft.com/fwlink/?linkid=14202")>]
member this.IsStartupScriptRegistered : string -> bool
Public Function IsStartupScriptRegistered (key As String) As Boolean

Parameters

key
String

The string key of the startup script to search for.

Returns

Boolean

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

Attributes
ObsoleteAttribute

Examples

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="C#"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<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.'} </");
      cstext2.Append("script>");
      RegisterClientScriptBlock(csname2, cstext2.ToString());
    }
  }
</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>


<%@ 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>

Remarks

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.

Applies to

See also