How I Do Handle Alert Message In Bootstrap

Question

i have a web application in which i have different form to get input from user,when user press save button a massage is displayed using this code in the site.master

<asp:UpdatePanel runat="server">

<asp:Literal runat="server" ID="_alert" >
<asp:ContentPlaceHolder runat="server" ID="MainContent">


and using script code as follow:
$(".alert").alert('close');

if i use this code then there is no error or successful message is displayed ,just all fields clear and ready for next entry.
and if i use (_alert) instead then message is displayed but it does not hide. i want that on each entry message is displayed and vanished after few second and form is ready for next entry.plz help me out