A bookmarklet for check the HTML with html-inspector( https://github.com/philipwalton/html-inspector ). Caution: May not work on all browsers for security restrictions.

min.js

void function(t){if(t.HTMLInspector!=null){t.HTMLInspector.inspect()}else{var e=document.getElementsByTagName("head")[0]||document.documentElement;var n=document.createElement("script");n.type="text/javascript";n.src="https://rawgithub.com/philipwalton/html-inspector/master/dist/html-inspector.js";n.onload=function(){t.HTMLInspector.inspect()};e.appendChild(n)}}(window);

plain.js

;void((function(w){
    if(w.HTMLInspector != null){
        w.HTMLInspector.inspect();
    } else {
        var head =
            document.getElementsByTagName('head')[0] ||
            document.documentElement;
        var script = document.createElement('script');
        script.type = 'text/javascript';
        script.src = 'https://rawgithub.com/philipwalton/html-inspector/master/dist/html-inspector.js';
        script.onload = function(){
            w.HTMLInspector.inspect();
        };
        head.appendChild(script);
    }
})(window));