By default, when clicking on a button of System.Web.UI.WebControls.Button in an ASP.NET page, it will always cause page postbacked.
If you want to a server button without postback triggered after cliking on it, you can do this by follwing the following steps:
1. Add a button of System.Web.UI.HtmlControls.HtmlInputButton to the page
2. Modify the button by adding runat="server":
<INPUT id="clickButton" type="button" value="Button" name="clickButton" runat="server">
3. Bind related Javascript function with the button
protected System.Web.UI.HtmlControls.HtmlInputButton clickButton;
private void Page_Load(object sender, System.EventArgs e)
{
...
clickButton.Attributes.Add("onclick", "javascriptfunction();");
clickButton.Value = "Click";
...
}
4. Export the corresponding Javascript function in the page or the attached Javascript file.