const div1 = document.getElementById("div1"); // one style css div1.style.color = "red"; // several style css div1.style.cssText = ` width: 500px; height: 500px; background: red; `;// Set a SINGLE CSS property: // css("propertyname"); $("p").css("background-color"); // Set MULTIPLE CSS Properties $("p").css({"background-color": "yellow", "font-size": "200%"});div.style.color = 'blue'; // adds the indicated style rule div.style.cssText = 'color: blue; background: white'; // adds several style rules div.setAttribute('style', 'color: blue; background: white'); // adds several style rulesvar element = document.createElement('select'); element.style.maxWidth = "100px";<script> function myFunction() { document.body.style.backgroundColor = "red"; } </script>//on HTML *Purist Style* || *Only JavaScript* <style> // .example { // para.style.color = 'white'; color: white; // para.style.background = 'black'; background-color: black; // para.style.padding = '10px'; padding: 10px; // para.style.width = '250px'; width: 250px; // para.style.textAlign = 'center'; text-align: center; } </style> // on JavaScript Element.setAttribute('class', 'highlight'); <html> <head> <style> .popup .popuptext { visibility: hidden; background-color: #555; color: #fff; text-align: center; border-radius: 6px; padding: 8px 0; z-index: 1; bottom: 125%; left: 50%; margin-left: -80px; } .popup .show { visibility: visible; -webkit-animation: fadeIn 1s; animation: fadeIn 1s; } @-webkit-keyframes fadeIn { from {opacity: 0;} to {opacity: 1;} } @keyframes fadeIn { from {opacity: 0;} to {opacity:1 ;} } </style> </head> <body style="text-align:center"> <div class="popup" onclick="myFunction()" ><button>Preview</button> <video class="popuptext" id="myPopup" style="width:800px;" > <source src="dolby-atmos-intro.mp4" type="video/mp4"> </video> </div> <script> function myFunction() { var popup = document.getElementById("myPopup"); popup.classList.toggle("show"); if (popup.paused){ popup.play(); } else{ popup.pause(); } } </script> </body> </html> Run code snippet<html> <style> </style> <script> </script> </html>