Core: introduce createHTMLDocument in parseHTML; Safari 8/IE8 left out

Close gh-1506

src/core/parseHTML.js

@@ -1,8 +1,13 @@
 define([
 	"../core",
 	"./var/rsingleTag",
-	"../manipulation" // buildFragment
-], function( jQuery, rsingleTag ) {
+
+	// This is the only module that needs core/support
+	"./support",
+
+	// buildFragment
+	"../manipulation"
+], function( jQuery, rsingleTag, support ) {
 
 // data: string of html
 // context (optional): If specified, the fragment will be created in this context,
@@ -16,7 +21,11 @@ jQuery.parseHTML = function( data, context, keepScripts ) {
 		keepScripts = context;
 		context = false;
 	}
-	context = context || document;
+	// document.implementation stops scripts or inline event handlers from
+	// being executed immediately
+	context = context || ( support.createHTMLDocument ?
+		document.implementation.createHTMLDocument( "" ) :
+		document );
 
 	var parsed = rsingleTag.exec( data ),
 		scripts = !keepScripts && [];

src/core/support.js

@@ -0,0 +1,15 @@
+define([
+	"../var/support"
+], function( support ) {
+
+support.createHTMLDocument = (function() {
+	if ( !document.implementation.createHTMLDocument ) {
+		return false;
+	}
+	var doc = document.implementation.createHTMLDocument( "" );
+	doc.body.innerHTML = "<form></form><form></form>";
+	return doc.body.childNodes.length === 2;
+})();
+
+return support;
+});