Backbone.JS PreviousAttributes()

The Backbone.JS PreviousAttributes() model is used to get the state of all the attributes prior to the last change event.

Syntax:

Model.PreviousAttributes ()

Example:

<title>Example</title>

var X = new Backbone.Model({

msg1: "HELLO WORLD.",

msg2: "Welcome."

});

X.set('msg1', 'Hello World.');

document.write("All the previous attributes of the model X before the change are: ");

document.write("<br>");

document.write(JSON.stringify(X.previousAttributes()));

</script>All the previous attributes of the model X before the change are: <br>{"msg1":"HELLO WORLD.","msg2":"Welcome."}

<title>Example</title> <script src="https://code.jquery.com/jquery-2.1.3.min.js" type="text/javascript"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js" type="text/javascript"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js" type="text/javascript"></script> <script type="text/javascript"> var X = new Backbone.Model({ msg1: "HELLO WORLD.", msg2: "Welcome." }); X.set('msg1', 'Hello World.'); document.write("All the previous attributes of the model X before the change are: "); document.write("<br>"); document.write(JSON.stringify(X.previousAttributes())); </script>All the previous attributes of the model X before the change are: <br>{"msg1":"HELLO WORLD.","msg2":"Welcome."}

  

  
Example  
  
  
  
  
  
All the previous attributes of the model X before the change are: 
{"msg1":"HELLO WORLD.","msg2":"Welcome."}

Output:

All the previous attributes of the model X before the change are:

{"msg1":"HELLO WORLD.","msg2":"Welcome."}

All the previous attributes of the model X before the change are: {"msg1":"HELLO WORLD.","msg2":"Welcome."}

All the previous attributes of the model X before the change are: 
{"msg1":"HELLO WORLD.","msg2":"Welcome."}

Explanation:
In the above example, all the previous attributes of the model X before the change are returned as the output.