Question

I would like to load different scripts if the user is on a smartphones/tablets or on a laptop.

Here is the result that I want :

Laptop:

<script src="http://code.jquery.com/jquery-1.8.2.min.js"></script> 

smartphones and tablets

<link rel="stylesheet" href="http://code.jquery.com/mobile/1.2.0/jquery.mobile-1.2.0.min.css" />
<script src="http://code.jquery.com/mobile/1.2.0/jquery.mobile-1.2.0.min.js"></script>

How can I do it?

Answer 1

You’re looking at either sniffing the User-Agent to detect for specific devices or you can use the browser/screen width to determine which category your user falls under.

To add scripts based on browser width you can do something like this:

<script src="http://code.jquery.com/jquery-1.8.2.min.js"></script>
<script>
    (function ($) {

        //check if the browser width is less than or equal to the large dimension of an iPad
        if ($(window).width() <= 1024) {

            //create an AJAX request for the CSS file
            $.ajax({
                url     : 'jquery.mobile-1.2.0.min.css',
                success : function (response) {
                    $('head').append('<style>' + response + '</style>');
                }
            });

            //create an AJAX request for the JS file, setting the dataType to 'script' will have jQuery automatically evaluate the JS code in the global scope
            $.ajax({
                url      : 'jquery.mobile-1.2.0.min.js',
                dataType : 'script'
            });
        }
    })(jQuery);
</script>

This has a few caveats though.

1. Small desktop browsers can be <=1024px wide so you’ll have some overlap between tablet and desktop users.
2. The JS/CSS needs to be hosted on your web server so you can access them without Cross-Domain-Policy issues.

The CSS/JS inclusion will most likely work for you no matter how you detect mobile/tablet devices. There are scripts out there to detect devices that run server-side as well as client-side, a quick Google search will bring up many of these scripts. I have not used these scripts however so I can’t offer much guidance on their usage.