Random odds in arrays

Okay, so let's say I store some of my data like this,

var thisList = {
    "items":[
        {"name":"Item1", "image":"/img/item1", "chance":0.25},
        {"name":"Item2", "image":"/img/item2", "chance":0.25},
        {"name":"Item3", "image":"/img/item3", "chance":0.50}
    ]           
}

Now I'd like to create a function that randomly picks a item out of this list with the chances being 25% of getting [0], another 25% of getting [1] and a 50% chance of getting [2]!

Is this possible? If so, how'd I do this?

Kind regards!