JS add HTML to page code example
Example 1: add element to body javascript
var elem = document.createElement('div');
elem.style.cssText = 'position:absolute;width:100%;height:100%;opacity:0.3;z-index:100;background:#000';
document.body.appendChild(elem);
Example 2: how to add elements in javascript html
//adding 'p' tag to body
var tag = document.createElement("p"); // <p></p>
var text = document.createTextNode("TEST TEXT");
tag.appendChild(text); // <p>TEST TEXT</p>
var element = document.getElementsByTagName("body")[0];
element.appendChild(tag); // <body> <p>TEST TEXT</p> </body>