In most browsers, the following would work. window.onload = function(){ console.log( document.getElementById('svgElm').getBoundingClientRect().width ); }; Here is a demo. If you try it in Google Chrome, the console will output 200. However, FireFox returns 0.
![How to get SVG element dimensions in FireFox?](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)