how to test a site structure or dom

I tring to generate some test over a page

I wonder if exists some jquery tool or similar where you can check if dome is correctly loaded. if this block existe, if that div have that class etc etc, maybe is some high but I want do an automatism that check certain syntax of my website.

I found test in postman but I cant check the dom there if you know some info about some tool that do this please tell me.

thanks in advance Emiliano