tag for example: sty, 
 write type of (sty) directly in js and output object, 
now I want to take the id of this tag as the type of object.
 tag for example: sty, 
 write type of (sty) directly in js and output object, 
now I want to take the id of this tag as the type of object.
I guess whether the question you want to ask is document.getElementById ('sty')
is the landlord just learning js
// idstydom
let styDom = document.querySelector('div-sharpsty') //API
// sty
// 
Object.prototype.toString.call(styDom)
dom:HTMLDivElement
13:51:59.133 "[object HTMLDivElement]"