How to make a button Default Button ?

Create a funtion

public static void MakeDefault(System.Web.UI.Page oPage, TextBox oTxt, ImageButton
oBtn)

{

StringBuilder sb = new StringBuilder();

sb.Append("<SCRIPT language='javascript'>");

sb.Append("function fnTrapKD(btn){");

sb.Append(" if (document.all){");

sb.Append(" if (event.keyCode == 13)");

sb.Append(" { ");

sb.Append(" event.returnValue=false;");

sb.Append(" event.cancel = true;");

sb.Append(" btn.click();");

sb.Append(" } ");

sb.Append(" } ");

sb.Append("}");

sb.Append("</SCRIPT>");

oTxt.Attributes.Add("onkeydown", "fnTrapKD(document.all."
+ oBtn.ClientID + ")");

oPage.RegisterStartupScript("ForceDefaultToScript", sb.ToString());

}

Call this function, eg: MakeDefault(Page, TextBox1, Button1)