use `` in js code example

Example 1: javascript template literals

//Must use backticks, `, in order to work.

let a = 5;
let b = 10;
console.log(`Fifteen is ${a + b} and
not ${2 * a + b}.`);

//Output:
//Fifteen is 15 and not 20.

Example 2: ${ js

`string text`

`string text line 1
 string text line 2`

`string text ${expression} string text`

tag `string text ${expression} string text`