Function to add class to body depending on font-size

functions.php

		<script>
			// Check if localStorage is supported
			if ('localStorage' in window && typeof localStorage == 'object') {
			  jQuery(document).ready(function($) {
			    // Set the class if black-white is set
			    // Note that localStorage saves everything as strings
			    if (localStorage["black-white"] == "1") {
			      $('html').addClass('black-white');
			    }

			    // Register click listener for the button
			    $('.black-white-button').click(function() {
			      // Toggle black-white on and off
			      if (localStorage["black-white"] != "1") {
			        $('html').addClass('black-white');
			        localStorage["black-white"] = "1";
			      }
			      else {
			        $('html').removeClass('black-white');
			        localStorage["black-white"] = "0";
			      }
			    }); // - button click


			    if (localStorage["font-size"] == "1") {
			      $('html').addClass('font-size');
			    }

			    // Register click listener for the button
			    $('.font-size-button').click(function() {
			      // Toggle black-white on and off
			      if (localStorage["font-size"] != "1") {
			        $('html').addClass('font-size');
			        localStorage["font-size"] = "1";
			      }
			      else {
			        $('html').removeClass('font-size');
			        localStorage["font-size"] = "0";
			      }
			    }); // - button click
			    
			  }); // - doc ready
			}
		</script>