JAVASCRIPT

create input element with js and append

var inputtime = document.createElement("input");
inputtime.setAttribute("type", "datetime");
inputtime.setAttribute("name", "milestones[]");
inputtime.setAttribute("value", "t_id");
inputtime.setAttribute("id", "dt");
inputtime.setAttribute("class", "form-control");
document.getElementById("rows").appendChild(inputtime);

append input using js

//Multiple Phone numbers inputs on Bootstrap using append

// https://bootsnipp.com/snippets/80ed5