Hi nadeem1218,
i can see many missing things in your code.
- Script is placed inside ContentPlaceHolder on Master page.
- Bootstrap and jquery both js missing.
- two title tag in head of master.
- ShowPopup Javascript function missing.
However i have corrected all the things in below sample code. please refer it, it works.
MASTER PAGE:
<head runat="server">
<title></title>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- Bootstrap -->
<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css"
rel="stylesheet">
<script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.8.3.min.js" type="text/javascript"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/js/bootstrap.min.js"
type="text/javascript"></script>
<script src="http://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
<script src="http://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<asp:ContentPlaceHolder ID="head" runat="server">
</asp:ContentPlaceHolder>
<script type="text/javascript">
function ShowPopup() {
$("[id*=btnShowPopup]").click();
}
</script>
<style>
.modal-backdrop { height: 100%; }
</style>
</head>
<body>
<form runat="server">
<asp:ContentPlaceHolder ID="MainContent" runat="server" />
</form>
</body>
aspx Page:
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="head">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<div class="modal fade" id="myModal" style="display: none">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span></button>
<h4 class="modal-title">
Registration done Successfully</h4>
</div>
<div class="modal-body">
Test Modal
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">
Close</button>
<button type="button" class="btn btn-primary">
Save changes</button>
</div>
</div>
</div>
</div>
<asp:Button runat="server" ID="btnShowPopup" Text="Test Show" OnClick="btn_click"
CssClass="btn btn-primary" data-toggle="modal" data-target="#myModal" />
</ContentTemplate>
</asp:UpdatePanel>
</asp:Content>
Code Behind:
protected void btn_click(object sender, EventArgs e)
{
ClientScript.RegisterStartupScript(this.GetType(), "alert", "ShowPopup();", true);
}
Thanks