How can I capture the default product variant ID with JavaScript?

Technical Q&A
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1

Could you please help with one liner JS code to get the default variant ID of the product? I want to capture the variant id when this page loads.

https://www.fabretro.com/products/engraved-20oz-pilsner-tumbler-i?_pos=1&_psq=test&_ss=e&_v=1.0&variant=42620336930972

Regards,

Pramod