angualar js

Adding watermark

<input type="text" ng-model="car.plate" placeholder="What's the plate?" />

Disable button till all mandatory field is filled

<input type="text" ng-model="car.plate" placeholder="What's the plate?" />

<input type="text" ng-model="car.model" placeholder="What's the Model" />

<button ng-click="park(car)" ng-disabled="!car.plate || !car.model">Park</button>