BackboneJS - Model Previous

Description

It determines the previous value of the changed attribute.

Syntax

model.previous(attribute)

Parameters

attribute − It represents the property of a model.

Example

Live Demo

<!DOCTYPE html>
<html>
   <head>
      <title>Model 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>
   </head>
   
   <body>
      <script type = "text/javascript">
         var model = new Backbone.Model ({
            id:01,
            player:'Sachin'
         });
         model.set('id', '02');
         document.write(
            "Value of id after set: ", JSON.stringify(model.changedAttributes()));
         
         document.write("<br>");
         document.write("The previous value of id is: ", model.previous('id'));
      </script>
      
   </body>
</html>

Output

Let us carry out the following steps to see how the above code works −

Save the above code in the previous.htm file.
Open this HTML file in a browser.

backbonejs_model.htm