set id for element html code example

Example 1: get id of element javascript

var element = document.getElementsByTagName("div")[0];
var id = element.id;

Example 2: html id

<style>
#grepperHeader {
  background-color: lightblue;
  color: navy;
  padding: 40px;
  text-align: center;
}
</style>

<h1 id="grepperHeader">grepperHeader</h1>