Detect pressed key with jquery

$(document).keypress(function(e) {
    if(e.which == 13) {      //13 is stand for Enter key
        alert('You pressed enter!');
    }
});

Show & Hide Gridview Cell with mouse hover asp

 $(document).ready(function () {

            $('<%# GridView1.ClientID%> tr td:nth-child(2)').hover(function () {
                $(this).next().css("visibility", "visible");            // show on mouse over on row
            });
            $('<%# GridView1.ClientID%> tr').mouseleave(function () {
                $('<%# GridView1.ClientID%> tr td:nth-child(3)').css("visibility", "hidden"); //hide on mouse leave from row
            });

});

Call Server Method on Button Hover ASP

 <asp:LinkButton ID="hoverButton" runat="server" OnClick="click" onmouseover="__doPostBack(this.id, '');" Text="Mouse Over Me" />