A little tv4 extension that can pre-fetch all required schemas.

tv4-asyncFetchSchemas.js

tv4.asyncFetchSchemas = function (urls, callback) {
	var activeRequests = 0;
	var attemptedRequest = {};
	if (!Array.isArray(urls)) urls = [urls];
	
	function requestFinished(url) {
		activeRequests--;
		
		var missing = tv4.getMissingUris();
		for (var i = 0; i < missing; i++) {
			if (!attemptedRequest[missing[i]]) {
				fetchSchema(missing[i]);
			}
		}
		
		if (activeRequests <= 0) {
			callback();
		}
	}
	
	function fetchSchema(url) {
		activeRequests++;
		attemptedRequest[url] = true;
		$.getJSON(url).success(function (schema) {
			tv4.addSchema(url, schema);
			requestFinished(url);
		}).error(function () {
			console.log("Error fetching schema: " + url);
			tv4.addSchema(url, {});
			requestFinished(url);
		});
	}
	
	urls.forEach(fetchSchema);
};