LayoutTests/svg/custom/js-late-gradient-creation.svg

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1 Basic//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-basic.dtd">  
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"  id="svg-root" width="100%" height="100%" viewBox="0 0 480 360" onload="createGradient()">
<g id="content" transform="scale(1, 1.5)">
     <text font-size="68" fill="url(#dynGrad)"  x="20" y="70">Gradient on fill</text>
</g>
<script>
	var content = document.getElementById("content");

	function createGradient()
	{
		var gradient = document.createElementNS("http://www.w3.org/2000/svg", "linearGradient");
		gradient.setAttribute("id", "dynGrad");
		gradient.setAttribute("x1", "0");
		gradient.setAttribute("x2", "1");

		var stop1 = document.createElementNS("http://www.w3.org/2000/svg", "stop");
		stop1.setAttribute("stop-color", "blue");
		stop1.setAttribute("offset", "0");

		var stop2 = document.createElementNS("http://www.w3.org/2000/svg", "stop");
		stop2.setAttribute("stop-color", "red");
		stop2.setAttribute("offset", "1");

		gradient.appendChild(stop1);
		gradient.appendChild(stop2);

		content.appendChild(gradient);
	}
</script>

</svg>