1-2 Vue Instance

    
    
    



    
{{ foo }}
    
    Change it



    hello



    var obj = {
        foo: 'bar'
    }

    Object.freeze(obj)

    new Vue({
        el: '#app',
        data: obj
    })
//------------------------
    var data = { a: 1 }
    var vm = new Vue({
        el: '#example',
        data: data
    })

    vm.$data === data // => true
    vm.$el === document.getElementById('example') // => true

    // $watch is an instance method
    vm.$watch('a', function (newValue, oldValue) {
        console.log(newValue,oldValue)
    })