I have an SVG file, and I don't want to paste it inside the HTML file because, well, it gets messy.
So after consulting with w3schools, embed tag seemed the safest way to include an external SVG file into HTML.

<embed src=path_to_svg type=image/svg+xml id='svgsource' />

However, I need to access the svg elements through DOM via javascript in the main html file. Unfortunately neither

document.getElementById('my_svg_id')

nor

document.getElementById('svgsource').contentDocument

works in any browser. Using object tag doesn't do the trick either.