Add allow_attributes parser rule option to do just that.

parser_rules/advanced.js

@@ -179,6 +179,9 @@ var wysihtml5ParserRules = {
             "rename_tag": "div"
         },
         "a": {
+            "allow_attributes": [
+                "title"
+            ],
             "check_attributes": {
                 "href": "url" // if you compiled master manually then change this from 'url' to 'href'
             },
@@ -188,6 +191,9 @@ var wysihtml5ParserRules = {
             }
         },
         "img": {
+            "allow_attributes": [
+                "title"
+            ],
             "check_attributes": {
                 "width": "numbers",
                 "alt": "alt",

parser_rules/simple.js

@@ -20,6 +20,9 @@ var wysihtml5ParserRules = {
     ol:     {},
     li:     {},
     a:      {
+      allow_attributes: [
+        "title"
+      ],
       set_attributes: {
         target: "_blank",
         rel:    "nofollow"

src/dom/parse.js

@@ -211,6 +211,7 @@ wysihtml5.dom.parse = (function() {
     var attributes          = {},                         // fresh new set of attributes to set on newNode
         setClass            = rule.set_class,             // classes to set
         addClass            = rule.add_class,             // add classes based on existing attributes
+        allowAttributes     = rule.allow_attributes,      // copy attributes from old to new node
         setAttributes       = rule.set_attributes,        // attributes to set on the current node
         checkAttributes     = rule.check_attributes,      // check/convert values of attributes
         allowedClasses      = currentRules.classes,
@@ -230,6 +231,17 @@ wysihtml5.dom.parse = (function() {
     if (setAttributes) {
       attributes = wysihtml5.lang.object(setAttributes).clone();
     }
+
+    if (allowAttributes) {
+      allowAttributesLength = allowAttributes.length;
+      for (i = 0; i<allowAttributesLength; i++) {
+        attributeName = allowAttributes[i];
+        newAttributeValue = _getAttribute(oldNode, attributeName);
+        if (typeof(newAttributeValue) === "string") {
+          attributes[attributeName] = newAttributeValue;
+        }
+      }
+    }
 
     if (checkAttributes) {
       for (attributeName in checkAttributes) {
@@ -270,7 +282,7 @@ wysihtml5.dom.parse = (function() {
       classes = classes.concat(oldClasses.split(WHITE_SPACE_REG_EXP));
     }
     classesLength = classes.length;
-    for (; i<classesLength; i++) {
+    for (i = 0; i<classesLength; i++) {
       currentClass = classes[i];
       if (allowedClasses[currentClass]) {
         newClasses.push(currentClass);

test/dom/parse_test.js

@@ -79,6 +79,7 @@ if (wysihtml5.browser.supported()) {
     var rules = {
       tags: {
         img: {
+          allow_attributes: [ "title" ],
           set_attributes: { alt: "foo", border: "1" },
           check_attributes: { src: "url", width: "numbers", height: "numbers", border: "numbers" }
         },
@@ -98,13 +99,13 @@ if (wysihtml5.browser.supported()) {
         '<h1 id="main-headline" >take this you snorty little sanitizer</h1>' +
         '<h2>yes, you!</h2>' +
         '<h3>i\'m old and ready to die</h3>' +
-        '<div><video src="pr0n.avi">foobar</video><img src="http://foo.gif" height="10" width="10"><img src="/foo.gif"></div>' +
+        '<div><video src="pr0n.avi">foobar</video><img src="http://foo.gif" height="10" width="10" title="Hell yeah!"><img src="/foo.gif"></div>' +
         '<div><a href="http://www.google.de"></a></div>',
         rules
       ),
       '<h2>take this you snorty little sanitizer</h2>' +
       '<h2>yes, you!</h2>' +
-      '<span><img alt="foo" border="1" src="http://foo.gif" height="10" width="10"><img alt="foo" border="1"></span>' +
+      '<span><img alt="foo" border="1" title="Hell yeah!" src="http://foo.gif" height="10" width="10"><img alt="foo" border="1"></span>' +
       '<span><i title=""></i></span>'
     );
   });