.id javascript code example

Example 1: javascript change element id

var element = document.getElementById("oldID");
element.id = "newID";

Example 2: get id of element javascript

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

Example 3: referance html id css

<style>
  #test {
  /*Styleing here*/
  }
</style>
<h1 id="test"></h1>