how to set attribute in javascript code example

Example 1: javascript update attribute

var element = document.getElementById("elemId");
element.setAttribute("attributeName", "value");

Example 2: javascript setattribute

element.setAttribute(<name>, <value>);
// ex
var aElement = document.querySelector("a"); 
aElement.setAttribute("href", "https://isitchristmas.com/"); 
// same as <a href="https://isitchristmas.com/"></a>

Example 3: setAttribute()

element.setAttribute(name, value);
element.setAttribute("style", "background-color: red;");

Example 4: set attribute javascript

Element.setAttribute(name, value);

Example 5: put new attribute on html tag using javascript

// Here's what you do for the style attribute
span.setAttribute("style", "width:110%;float:center;left-margin:-10px;top-margin:-10;");

Example 6: set property dom javascrpt

document.getElementsByTagName("H1")[0].setAttribute("class", "democlass");