Add hook for extracting protocol from URLs

packages/morph/lib/dom-helper.js

@@ -403,4 +403,16 @@ prototype.parseHTML = function(html, contextualElement) {
   }
 };
 
+var parsingNode;
+
+// Used to determine whether a URL needs to be sanitized.
+prototype.protocolForURL = function(url) {
+  if (!parsingNode) {
+    parsingNode = this.document.createElement('a');
+  }
+
+  parsingNode.href = url;
+  return parsingNode.protocol;
+};
+
 export default DOMHelper;

packages/morph/tests/dom-helper-test.js

@@ -372,6 +372,16 @@ test('#parseHTML of number', function(){
   equalHTML(nodes, '5');
 });
 
+test('#protocolForURL', function() {
+  var protocol = dom.protocolForURL("http://www.emberjs.com");
+  equal(protocol, "http:");
+
+  // Inherit protocol from document if unparseable
+  protocol = dom.protocolForURL("   javascript:lulzhacked()");
+  /*jshint scripturl:true*/
+  equal(protocol, "javascript:");
+});
+
 test('#cloneNode shallow', function(){
   var divElement = document.createElement('div');