How Polymer observes changes on an element’s properties in Polymer.js?

Polymer observes changes on any element’s properties by taking following actions.

• Observers: It invokes the callbacks whenever any kind of data changes takes place.
• Computed Properties: It computes the virtual properties based on other properties of the elements, and then re-computes them whenever the input data changes.
• Data Bindings: It updates the properties, attributes, or the text content of a DOM node using annotations whenever the data changes take place.