History.js HTML4 / HTML5 parity

gistfile1.js

// save hash value for HTML5 browsers arriving to site via HTML4 hashed url
// this should be done before $(document).ready and History.js is loaded
window.initHash = window.location.hash;

$(document).ready(function() {
	var baseURL = History.getBaseUrl(),
		currentURL = History.getState().url,
		relativeURL = currentURL.replace( baseURL, '' );

	if ( !Modernizr.history && currentURL !== baseURL ) {
		// if browser doesn't support HTML5 history and this isn't the root url,
		// redirect to the root url + hash
		document.location.href = baseURL + '#./' + relativeURL;
		return;
	} else if ( Modernizr.history && window.initHash.length ) {
		// if this browser supports HTMLS history and the initial url included a hash,
		// load the content via ajax (assumes load method is defined elsewhere)
		load( History.getState().url );
	}
});