Button to navigate to articles from Nature publications which are published before DOIs are assigned - clicking the bookmarklet uses Nature's search engine to find the correct article and navigates there (copy the text as a bookmark, the other file is there for reference)

bookmarklet

javascript:(function(){if (window.location.href.indexOf('nature.com/doifinder/') > -1 && document.querySelector('span.largeParagraph > p').innerText.indexOf('DOI Handle') > -1) { doi = window.location.href.split('doifinder/')[1]; var naturexhr = new XMLHttpRequest(); naturexhr.open("GET","http://www.nature.com/search/executeSearch?sp-q="+doi.replace('/','%2F')+"&sp-p=all&pag-start=1&sp-c=25&sp-m=0&sp-s=&siteCode=default,true"); naturexhr.send(); naturexhr.onreadystatechange = function(){ if (naturexhr.readyState === 4 && naturexhr.status==200){ redirURL = naturexhr.response.match(/<h2 class="atl"><a href="(.*?)"/)[1]; window.location.href = redirURL; } } } else { alert('You need to be on the error page to do page redirect from the "invalid DOI" page'); }
})();

invaliddoi.js

if (window.location.href.indexOf('http://www.nature.com/doifinder/') > -1 && document.querySelector('span.largeParagraph > p').innerText.indexOf('DOI Handle') > -1) {
	doi = window.location.href.split('doifinder/')[1];
	var naturexhr = new XMLHttpRequest();
	naturexhr.open("GET","http://www.nature.com/search/executeSearch?sp-q="+doi.replace('/','%2F')+"&sp-p=all&pag-start=1&sp-c=25&sp-m=0&sp-s=&siteCode=default,true");
	naturexhr.send();
	naturexhr.onreadystatechange = function(){
		if (naturexhr.readyState === 4 && naturexhr.status==200){
			redirURL = naturexhr.response.match(/<h2 class="atl"><a href="(.*?)"/)[1];
			window.location.href = redirURL;
		}
	}
}
else {
	alert('You need to be on the error page to do page redirect from the "invalid DOI" page');
}