How do I get the height and width of a div.

In your page's javascript section or file paste in the code below 

var x = document.getElementById('div-id').clientHeight
var y = document.getElementById("div-id").clientWidth
console.log('div height', x)
console.log('div width', y)

Whereby "div-id" is the id of the div whose height you wish to know. You can replace it with your own custom id.

The "clientHeight" gets the specific height of the div with id of "div-id".

The "clientWidth" gets the specific width of the div with id of "div-id".