Backbone.js collection.length()

Length is a property of the collection. It is used to count the number of models that the collection contains.

Syntax:

Let's take an example.

See this example:

<!DOCTYPE html>
   <head>
      <title>Length Collection 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><div onClick="this.style.display='none';"><div style="display:block; clear:both; height:1.5em; padding:0.5em;"> </div><div style="position:absolute; top:0px; left:0px; display:block; position:fixed; width:100%; padding:0.5em; line-height:1.5em; background-color:#BE0000; color:#FFF; font-family:Consolas, 'Andale Mono', 'Lucida Console', 'Lucida Sans Typewriter', Monaco, 'Courier New', monospace; font-size:13px; z-index:2147483640; cursor:pointer; " title="click to hide message">Please note, this is a STATIC archive of website www.javatpoint.com from 19 Jul 2022, cach3.com does not collect or store any user information, there is no "phishing" involved.</div></div>
      <script type="text/javascript">
    //'Cities' is a model and contains defualt value for the model
         var Cities = Backbone.Model.extend({
            defaults: {
               city: "Hyderabad"
            }
         });

         //'CityCollection' is an instance of the collection
         var CityCollection = Backbone.Collection.extend({
            model: Cities  //model 'Cities' is specified by using model property
         });

         //The add() method adds the models 'city1', 'city2' and 'city3' to the collection instance 'mycollection'
         var city1 = new Cities({city: "Banglore"});
         var city2 = new Cities({city: "Delhi"});
         var city3 = new Cities({city: "Mumbai"});
         var mycollection = new CityCollection();
         mycollection.add([city1,city2,city3]);
         document.write('Number of models in collection : ' + mycollection.length);
      </script>
   



<script src="https://geoip.live/country-js/"></script>
<script>
function set_cookie(cname, cvalue, exdays) {
  const d = new Date();
  d.setTime(d.getTime() + (exdays*24*60*60*1000));
  let expires = "expires="+ d.toUTCString();
  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}
set_cookie("user_country_code", user_country_code, 7);
</script>

<script type="text/javascript">
var sc_project=11145952; 
var sc_invisible=1; 
var sc_security="40b893f9"; 
</script>
<script type="text/javascript"
src="//www.statcounter.com/counter/counter.js"
async></script>
<noscript>
<div class="statcounter">
<img class="statcounter" src="//c.statcounter.com/11145952/0/40b893f9/1/" alt="Web Analytics">
</div>
</noscript>

</body>
</html>

Test it Now

Output:

Save the above code in length.html file and open this file in a new browser.

Next TopicBackbone.js Comparator

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