Like @media breakpoints from CSS, but for JavaScript.

Do you have a responsively designed web page with lots of JavaScript that you want to load on the desktop, but not on mobile? This will handle that for you. Designate a minWidth and/or a maxWidth in pixels; your script will only load and execute when the screen is the right width.

To use, call responsiveJS.register() with an object bearing these properties (all of which are optional):

• name: Name of your script. Used in various console.logs to let you know what's going on.
• url: You can designate a .js file to be loaded and run when the screen is the right size.
• activationFunction: A function to be run when the screen is the right size.
• deactivationFunction: A function to be run when the screen is no longer the right size. You can combine this with the above to have JavaScript features that turn on and off as the window gets resized.
• minWidth: Run activationFunction and the script downloaded from url when the screen is at least this size. Run deactivationFunction if the screen gets smaller than that.
• maxWidth: Run activationFunction and the script downloaded from url when the screen is smaller than this. Run deactivationFunction if the screen gets too big.

You can call responsiveJS.register() multiple times with different combinations of settings, like so:

responsiveJS.register({
  name: "Desktop script",
  minWidth: 1200,
  url: "bigFile.js",
  activationScript: function() {
    console.log("Desktop mode");
    // do desktop things
  },
  deactivationScript: function() {
    // stop doing desktop things
  }
});
responsiveJS.register({
  name: "Mobile script",
  maxWidth: 1200,
  activationScript: function() {
    console.log("Mobile mode");
    // do mobile things
  },
  deactivationScript: function() {
    // stop doing mobile things
  }
});