The href read-only property of the SVGGradientElement interface reflects the href or xlink:href attribute of the given element.
href property<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200">
<defs>
<linearGradient id="gradient1">
<stop offset="0%" stop-color="red" />
<stop offset="100%" stop-color="blue" />
</linearGradient>
<linearGradient id="gradient2" href="#gradient1" />
</defs>
<rect x="10" y="10" width="180" height="180" fill="url(#gradient2)" />
</svg>const gradient = document.getElementById("gradient2");
console.log(gradient.href.baseVal); // Output: "#gradient1"