Since respond.js doesn't trigger any events or provide any way of applying a callback function, your only option is to modify respond.js to have it trigger an event.
I suggest modifying this line:
https://github.com/scottjehl/Respond/blob/master/src/respond.js#L298
if (requestQueue.length) {
var thisRequest = requestQueue.shift();
ajax(thisRequest.href, function (styles) {
translate(styles, thisRequest.href, thisRequest.media);
parsedSheets[thisRequest.href] = true;
// by wrapping recursive function call in setTimeout
// we prevent "Stack overflow" error in IE7
w.setTimeout(function () {
makeRequests();
}, 0);
});
}/* from here on was added*/ else {
var event = new Event("respondFinished");
document.dispatchEvent(event);
}
Now you can add an event listener to the document in the scripts that need it.
if (window.respond.mediaQueriesSupported) {
doSomething();
} else {
$(document).on("respondFinished", doSomething);
}
You'll want to add this event handler as soon as possible, preferably before document ready to ensure that the event gets bound before respond.js finishes.