how to apply onfocus in mvc4 razor

@if (@Model != null)
{
@grdTaxType.GetHtml(
tableStyle: "webgrid webgridwidth",
headerStyle: "webgridheader",
alternatingRowStyle: "webgridaltrowstyle",
selectedRowStyle: "select",
rowStyle: "webgridrowstyle",
footerStyle: "webgridfooter",
columns: grdTaxType.Columns(


grdTaxType.Column(header: "From Date",format: (item) => Html.TextBox("txtFromdate", null, new { ID = "txtFromdate" })),

grdTaxType.Column(header: "To Date", format: (item) => Html.TextBox("txttodate", null, new { ID = "txtFromdate" })),

grdTaxType.Column(header: "Percentage", format: (item) => Html.TextBox("percentage", null,new { ID = "txtFromdate" })),

grdTaxType.Column(header: "Delete", format: @<text><img

src="../../Image/delete.GIF" alt="" style="border: none;" />)

))
}