Userscript to add 'o' shortcut to the new Twitter. Opens shared links, @reply usernames, hashtags shared in a tweet, in that order of priority

newTwitterOpenLinkShortcut.user.js

// ==UserScript==
// @name        'o' shortcut for new Twitter
// @description Adds an 'o' shortcut to open any shared links in selected tweet in a new tab in the background. If no link is found, looks for @usernames. And finally if no usernames, looks for hashtags.
// @include     http://twitter.com/*
// @author      Ankit Ahuja
// ==/UserScript==

// DISCLAIMER: Only tested on Chrome!

document.addEventListener('keyup', function(e) {
    var tag = e.target.tagName.toLowerCase();
    // keycode for 'o' is 79/111
    if (tag == 'input' || tag == 'textarea' || e.keyCode != 79)
        return true;
    var h_el = document.getElementsByClassName('hovered-stream-item');
    if (h_el.length != 0) {
        // find links
        var links = h_el[0].getElementsByClassName('twitter-timeline-link');
        if (links.length != 0) {
            // open the first found link in a background tab. TODO: Add ability to open multiple links
            simulateClick(links[0], true);
            return true;
        }
        // otherwise, simulate a click on first found @username in tweet
        var user = h_el[0].getElementsByClassName('twitter-atreply');
        if (user.length != 0) {
            simulateClick(user[0]);
            return true;
        }
        
        // finally, look for hashtags. if found, open in a background tab
        var hashtag = h_el[0].getElementsByClassName('twitter-hashtag');
        if (hashtag.length != 0) {
            simulateClick(hashtag[0], true);
            return true;
        }
    }
}, true);

function simulateClick(el, target) {
	var evt = document.createEvent("MouseEvents");
	//on Mac, pass target as e.metaKey
	if (navigator.platform.indexOf("Mac") != -1)
		evt.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, false, false, false, target, 0, null);
	else //otherwise, pass target as e.ctrlKey	
		evt.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, target, false, false, false, 0, null);
	return el.dispatchEvent(evt);
}