GZipped: 631 bytes
Minified: 1079 bytes
Compatibility: Tested in Safari, Chrome, Firefox, IE6+, basically doing nothing too fancy.
Examples: http://berklee.github.com/nbl/example.html
NBL.js is a tiny script that will make your HTML pages load faster by loading all your JavaScript files
asynchronously (in parallel) with the rest of your page. Normally if you include two or three scripts
in your page, the browser will wait for them to be executed before your page is shown.
By using NBL.js the browser can start showing the HTML while loading and executing the scripts, resulting
in a faster, more responsive website. All in less than 1kb!
- Load scripts asynchronously or in order, or any combination of both
- Every script can have its own callback
- A callback for loading all items
- Can be mixed with your provided function for loading some data
- [TODO: Trigger a callback on a user definable timeout period]
- Uses HTML5’s data attribute for configuration, so load all scripts with one script-tag
- Very small code!
Include NBL.js in your pages and let it dynamically load all your JavaScript files by simply including
the following tag:
<script src="nbl.js" data-nbl="[ { load: 'http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js',
then: ['jquery.lightbox.min.js', 'jquery.carousel.min.js' ],
callback:function(e){ jquery_loaded(e) }
},
'http://www.google-analytics.com/urchin.js' ]"></script>
This will do the following:
- It will load the latest version of jQuery.
- It will load the Urchin script from Google Analytics.
- After jQuery has loaded, it will start loading the jQuery plugins as defined after jQuery in parallel.
- When jQuery has loaded, it will call the
jquery_loaded()function. - Finally, when Urchin has loaded, it will call the
urchin_loaded()function.
NBL.js is rather flexible in its options, so let’s dissect a few examples.
[ 'script1.js', 'script2.js', 'script3.js' ]
This will simply load all three scripts in parallel.
[ {load:'script1.js', then:['plugin1.js', 'plugin2.js' ]}, 'script2.js' ]
This will load script1.js and script2.js in parallel. After script1.js has loaded, plugin1.js and
plugin2.js will load in parallel.
{ load:'script1.js', then:{load:'script2.js', then:{load:'script3.js, then:'script4.js } } }
It’s a bit crazy, but nesting the objects like this will allow you to load all scripts sequentially.
[ {load:'script1.js', callback:function(e){ script1_callback(e) }},
{load:'script2.js', callback:function(){ script2_callback() }},
{load:'script3.js', callback:function(){ script3_callback() }} ][ { load:'script1.js',
then: {load:'plugin1.js', callback:function(){ plugin1_callback() } },
callback: function(e){ script1_callback(e) }
},
{load:'script2.js', callback:function(){ script2_callback() }} ]{ load: ['script1.js', 'script2.js', 'script3.js' ], timeout: function(){global_timeout()} }{
If you prefer you can choose to simply include NBL.js in a single line in your HTML pages. This way you can
save a HTTP-call from the browser, and it will only add 900 bytes to your HTML page. Simply include the code
in nbl.single.js into a <script> tag at the end of your page, and replace ['your', 'scripts', 'here']
with your own options.
You can’t use the data-nbl attribute of the script tag if you use this method.
All options are case-sensitive, if you include a file called urCHin.js, the corresponding nbl.q object
will be nbl.q.urCHin. I advise you to simply use lowercase for all options.
If you do not specify any options in the script tag, NBL.js will instantiate the default nbl object and will
do nothing. You will have to do a manual nbl.l( [ 'options', 'here' ] ).
You can find more examples in the included example.html.
I hope you find NBL.js useful, thanks for reading this!
Berklee
(@Berklee on Twitter or feedback at berkl.ee)
GitHub user Knowlecules mailed me with modifications to preload CSS and images using NBL.js. I’ve incorporated
that code into nbl.plus.js (and nbl.plus.min.js). Thanks to some additional bug squashing by Richard Lopes,
the latest version of NBL Plus is now better than ever! Clocking in at 1154 bytes for the minified version and
694 bytes for the gzipped one, there’s no reason not to use NBL Plus for your asynchronous media loading needs.
Copyright © 2009-2011 Berklee
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