you have to use "document.createElementNS("http://www.w3.org/2000/svg", "svg");"
to create svg elements
var container = document.createElement("div");
var svg = document.createElementNS("http://www.w3.org/2000/svg", "svg");
var circle = document.createElementNS("http://www.w3.org/2000/svg", "circle");
circle.setAttribute("cx", "20");
circle.setAttribute("cy", "20");
circle.setAttribute("r", "15");
svg.appendChild(circle);
container.appendChild(svg);
document.body.appendChild(container);