lightweight javascript plugin for image lazy loading
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justlazy.js Build Status Sauce Test Status

Lightweight javascript plugin to lazy load responsive images. Most of the existing javascript plugins using extensive dependencies or supporting just the img-tag without responsive parts. This plugin is supposed to be an alternative.

>> View demo and usage

>> View history and migration path

  • 100% performance with plain javascript (no jQuery)
  • 100% valid HTML (no empty src tag)
  • Simplicity and lightness (just lazy loading of images, no special cases)
  • Heavily tested on various devices, browsers and OS versions
Sauce Test Status


file include

You can download the latest release and include the justlazy.js file as follows in your page:

<script src="javascript/justlazy.js" type="text/javascript"></script>

If you want to use the lazy spinner, following css file is needed:

<link href="stylesheets/justlazy.css" type="text/css" rel="stylesheet">


$ npm install justlazy


Import the CSS file:

@import "justlazy/src/justlazy.css";

Import/require the JavaScript file:

var justLazy = require('justlazy/src/justlazy.js');


import justLazy from 'justlazy/src/justlazy.js';


Just feel free to contribute ..

Project setup

To set up the project you need the grunt-cli:

$ sudo npm install -g grunt-cli

Then you just have to clone the repository and run the install command:

$ npm install


To run tests manually you can use the $ grunt command to perform jshint and jasmine tests with phantomjs. Furthermore you can run $ grunt server to call the jasmine runner in your browser localhost:9999

Continuous Integration

justlazy has CI set up through Travis CI and Sauce Labs (free for open-source projects). Pull-request and checkins will be tested automatically.