how to add style in html using javascript code example

Example 1: add style javascript

// Bad:
element.setAttribute("style", "background-color: red;");
// Good:
element.style.backgroundColor = "red";

Example 2: how to give css style in javascript

document.getElementById("myH1").style.color = "red";

Example 3: how to change css using javascript

document.getElementById("myText").className = "anyNewClass"