get day number from new date javascript code example

Example: javascript get day

var d = new Date();
var n = d.toLocaleString("en-US", { "weekday": "long" }); // Monday
n += "\n" + d.toLocaleString("en-US", { "weekday": "short" }); // Mon
n += "\n" + d.toLocaleString("en-US", { "weekday": "narrow" }); // M