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Is it possible to know the elements old value and new value when it is changed dynamically?

An example, I have a button with value 190

<button name="btn1" directiveX>190</button>

And this button will be changed dynamically by socket.io. When its changed, I need to pare these values, if the new value higher then the old value is.

Thank You!

Is it possible to know the elements old value and new value when it is changed dynamically?

An example, I have a button with value 190

<button name="btn1" directiveX>190</button>

And this button will be changed dynamically by socket.io. When its changed, I need to pare these values, if the new value higher then the old value is.

Thank You!

  • javascript
  • angularjs
Share Improve this question asked Oct 22, 2012 at 13:20 VuralVural 8,74611 gold badges42 silver badges58 bronze badges
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1 Answer 1

Reset to default 6

If you $watch the value in your scope, it will give you the old value and the new value. So your link function in the directive would look like this

link: function(scope, element, attrs) {
         scope.$watch("foo", function(newVal, oldVal) {
           //logic based on oldVal
         }
      }

And then in your HTML

<button name="btn1" directiveX>{{foo}}</button>

See http://docs.angularjs/api/ng.$rootScope.Scope

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