How to extract an object from an array, from a JSON with JavaScript

As you can extract from an array object, a common value in json and print that value with javascrip.

This is my code:

var dogs = [{ 'name':'Chewie', 'size': 'medium', 'weight': 80 },
            { name:'Clifford', 'size': 'large', 'weight': 280 },
            { name:'Pongo', 'size': 'medium', 'weight': 120 }];