js-svg.js

function setAttrs(obj, attrs) {
  _.each(attrs, function(value, attr) {
    obj.setAttribute(attr, value);
  });
};

var paper = document.getElementById("js-svg");
var svgns = "http://www.w3.org/2000/svg";
var svg = paper.appendChild(document.createElementNS(svgns,"svg"));
var rect = svg.appendChild(document.createElementNS(svgns,"rect"));
setAttrs(svg, {width: 768, height: 200});
setAttrs(rect, {x: 68, y: 50, width: 632, height: 100,
                fill: "blue"});