Made a super quick bookmarklet for displaying the current screen dimensions for Chrome

bookmarklet-screendimensions.js

javascript:(function(w, d){
    var el = d.createElement('div');
        el.setAttribute('style', 'position: fixed; right: 1em; top: 0; background-color: red; color: white; padding: 5px; z-index: 1000;');
    el.innerHTML = d.documentElement.clientWidth;
    d.body.appendChild(el);
    w.addEventListener('resize', function(){
        el.innerHTML = d.documentElement.clientWidth;
    }, false);
}(window, window.document));

// minified version
/* 
javascript:(function(w,d){var el=d.createElement("div");el.setAttribute("style","position: fixed; right: 1em; top: 0; background-color: red; color: white; padding: 5px; z-index: 1000;");el.innerHTML=d.documentElement.clientWidth;d.body.appendChild(el);w.addEventListener("resize",function(){el.innerHTML=d.documentElement.clientWidth},false)})(window,window.document);
*/