How to make the webgrid first row data is selected(highlighted) when a razor view is loaded?

Question

I am using webgrid in the razor view of my mvc web app, a razor view contains a webgrid, I want to make the first row data to be selected by default when the page is loaded every time.

A .css called "selectRow" has been created as this:

.selectRow {
 background: black;
 color : white;}

I have tried this, but it doesn't work, any idea how to make it working? much appreciated! the "WebgridId" is the htmlAttributes of current webgrid

$(document).ready(function () {
    $('#WebgridId tr').find("first").addClass('selectRow');
})