main.js

/**
 * Get the editable instance.
 */
let editable = document.querySelector('[contenteditable=true]');

/**
 * When focus is removed, run the `formatText` function
 */
editable.addEventListener('blur', formatText);

/**
 * Format the innerText of the SpongeBob meme
 */
function formatText(event) {
	/* Format the text
	 * Split the text into an array, for each character in the array, if the index of the letter is odd,
	 * return the letter uppercase, otherwise return it lowercase
	 * then join the array with no delimiter returning it to a normal string
	 */
	this.innerText = this.innerText
		.split('')
		.map(function(letter, i) {
			return i % 2 ? letter.toUpperCase() : letter.toLowerCase();
		})
		.join('');
}