Javascript Alert in ASP.NET

Question

I want to use Javascript Alert function in my ASP.NET page.

For example like this;

Response.Write("<script language=javascript>alert('ERROR');</script>);

But, this doesn't work.

I ask in here what am i doing wrong and everyone suggest me using RegisterScriptBlock

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), " ", "alert('ERROR')",true);

But i don't want use it because it's working with PostBack

How can i do that without PostBack ?

EDIT: For example for using;

try
{
    string strConnectionString = ConfigurationManager.ConnectionStrings["SqlServerCstr"].ConnectionString;

    SqlConnection myConnection = new SqlConnection(strConnectionString);
    myConnection.Open();

    string hesap = Label1.Text;
    string musteriadi = DropDownList1.SelectedItem.Value;
    string avukat = DropDownList2.SelectedItem.Value;

    SqlCommand cmd = new SqlCommand("INSERT INTO AVUKAT VALUES (@MUSTERI, @AVUKAT, @HESAP)", myConnection);

    cmd.Parameters.AddWithValue("@HESAP", hesap);
    cmd.Parameters.AddWithValue("@MUSTERI", musteriadi);
    cmd.Parameters.AddWithValue("@AVUKAT", avukat);
    cmd.Connection = myConnection;

    SqlDataReader dr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
    Response.Redirect(Request.Url.ToString());
    myConnection.Close();
}
catch (Exception)
{
    Response.Write("<h2>ERROR</h2>");
}

Answer 1

See a note from MSDN :

If you want to register a script block that does not pertain to partial-page updates, and if you want to register the script block only one time during initial page rendering, use the RegisterClientScriptBlock method of the ClientScriptManager class. You can get a reference to the ClientScriptManager object from the ClientScript property of the page.

So, I think ClientScriptManager.RegisterStartupScript method is what you need:

ClientScriptManager cs = Page.ClientScript;
cs.RegisterClientScriptBlock(
    this.GetType(), 
    " ", 
    @"<script language=javascript>alert('ERROR');</script>", 
    true
);

Answer 2

In your code you forgot the quotation mark. I just tried it in a sample page like this:

Response.Write("<script language=javascript>alert('ERROR');</script>");

and it worked. Where did you place the Response.Write in your code? Could you give some more details? What do you want to do?

Answer 3

For displaying an alert message to the User, in a webpage i have a code have a look at this

public void UserMsgBox(string sMsg)
{
StringBuilder sb = new StringBuilder();
System.Web.UI.Control oFormObject = null;
sMsg = sMsg.Replace("'", "\\'");
sMsg = sMsg.Replace(Strings.Chr(34), "\\" + Strings.Chr(34));
sMsg = sMsg.Replace(Constants.vbCrLf, "\\n");
sMsg = "<script language='javascript'>alert(\"" + sMsg + "\")</script>";
sb = new StringBuilder();
sb.Append(sMsg);
foreach (System.Web.UI.Control oFormObject_loopVariable in this.Controls) {
    oFormObject = oFormObject_loopVariable;
    if (oFormObject is HtmlForm) {
        break; // TODO: might not be correct. Was : Exit For
    }
}
oFormObject.Controls.AddAt(oFormObject.Controls.Count, new LiteralControl(sb.ToString()));
}

Answer 4

try using RegisterStartupscript for registering the script. Refer : http://msdn.microsoft.com/en-us/library/system.web.ui.page.registerstartupscript.aspx