how to get the value of id in html code example

Example 1: getelementbyid

document.getElementById("someid");

Example 2: Finding HTML Element by Id

var myElement = document.getElementById("intro");

Example 3: js get id value

var element = document.getElementById("YourElementId");
var value_element = document.getElementById("YourElementId").value;

Example 4: lxml.html get element by id

element = root.get_element_by_id("hello")

Example 5: how do i set an id for a div in js

All currently used browsers:
element.id=id;
myElement.id=newId;

element.className=class;
myElement.className=newClassName;