how to display a variable in javascript code example

Example 1: how to print a line in javascript

console.log("Your line would be here")//Prints a line on the console 
alert("Your message here")//Raises an alert

Example 2: how to print the value of variable in javascript in html

var name="kieran";
document.getElementById("output").innerHTML=name;

and the html code would be: 

<p id="output"></p>

Example 3: js variable html

<div onload="document.innerHTML(name + ' is ' + age)">