createdCallbackcreatedAn instance of the element is created.
-readyThe  has been fully prepared (e.g. shadow DOM created, property observers setup, event listeners attached, etc).
attachedCallbackattachedAn instance of the element was inserted into the DOM.
-domReadyCalled when the element’s initial set of children are guaranteed to exist. This is an appropriate time to poke at the element’s parent or light DOM children. Another use is when you have sibling custom elements (e.g. they’re.innerHTML‘d together, at the same time). Before element A can use B’s API/properties, element B needs to be upgraded. The domReady callback ensures both elements exist.
detachedCallbackdetachedAn instance was removed from the DOM.
attributeChangedCallbackattributeChangedAn attribute was added, removed, or updated. Note: to observe changes to published properties, use changed watchers.
Polymer parses element definitions and handles their upgrade asynchronously. If you prematurely fetch the element from the DOM before it has a chance to upgrade, you’ll be working with an HTMLUnknownElement. Polymer elements also support inline resources, such as stylesheets, that need to be loaded. These can causeFOUC issues if they’re not fully loaded prior to rendering an element. To avoid FOUC, Polymer delays registering elements until stylesheets are fully loaded.
To know when elements have been registered/upgraded, and thus ready to be interacted with, use thepolymer-ready event.

   rel="import" href="path/to/x-foo.html">

Polymer object lifecycle

Polymer('tag-name', {
  created: function() { ... },
  ready: function() { ... },
  attached: function () { ... },
  domReady: function() { ... },
  detached: function() { ... },
  attributeChanged: function(attrName, oldVal, newVal) {
    //var newVal = this.getAttribute(attrName);
    console.log(attrName, 'old: ' + oldVal, 'new:', newVal);


Insert Image into Github readme

Following syntax

![Title to be displayed](source of image, URL for image)

!: is for embedded  page of readme

Setup presentation library with bower

I have set up following libraries.

  • spring 3.2.4(jackson-1.9.13 for json resolver)
  • polymer
  • bower


Working on Google App Engine with Spring

I am not quiet sure that Google App Engine supports 'spring framework' well, yet.

I tried to generate google-app-engine project with mvn then import this project into eclipse in order to code in easy way. But it doesn't run......

Where can I start it?
Shall i just follow developer.google.com tutorial, mvn cli?

I believe using ide like eclipse is better choice for developer specially kind of me.
Any way  I will find a way more convenient approach.