Step 1 :
Write below code template file :
=========================
var _rys = jQuery.noConflict();
_rys("document").ready(function(){
_rys(window).scroll(function () {
if (_rys(this).scrollTop() > 136) {
_rys('#menubar').addClass("f-menublock");
} else {
_rys('#menubar').removeClass("f-menublock");
}
});
});
==========================
(#menubar) the div which will be fixed to top as it will add below class in that div. Write down your template div name here.
Step 2 :
Add this css in custom.css file :
==========================
.f-menublock {
margin: auto;
z-index: 9999;
position: fixed;
top: 0;
width: 965px;
}
===========================
Done !