Convert Latitude/Longitude Pair to Tile Coordinates

gistfile1.js

function latLngToCoords(zoom,lat,lon) {
    var n = Math.pow(2,zoom);

    var lat_rad = lat * (Math.PI / 180);

    var x_coord = n * ((lon + 180) / 360);

    var y_coord = .5 * n * (1 - (Math.log (Math.tan(lat_rad) + (1/Math.cos(lat_rad))) /  Math.PI));

    return {x: Math.floor(x_coord), y: Math.floor(y_coord)};
}