HTML Sanitizer src Attribute

[DylanBlumenberg]

Hi all, I'm attempting to add to the HTML Sanitizer Config whitelist so it only allows iframe URLs from "https://scribehow.com/embed/". I have the HTML Sanitizer Config set to the following but it's not blocking other URLs? What am I doing wrong?

var HTMLSanitizerConfig = Class.create();
HTMLSanitizerConfig.prototype = {
	initialize: function() {
	},
	
	HTML_WHITELIST : {
		globalAttributes: {
			attribute:[],
			attributeValuePattern:{}
		},
		iframe:{ 
			attribute:["width", "height","src","frameborder","allow","allowfullscreen"], attributeValuePattern: {src: /^https:\/\/scribehow\.com\/embed\//}
			}
			},
	
	HTML_BLACKLIST : {
		globalAttributes: {},
	},
	
	getWhiteList : function() {
		return this.HTML_WHITELIST;
	},
	
	getBlackList : function() {
		return this.HTML_BLACKLIST;
	},
	
	type: 'HTMLSanitizerConfig'
};