Show Password Pro.

Double click to switch password field: YELLOW (pop up tooltip with password); BULE (mouse over to show password); NORMAL (hide password);

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        Show Password Pro.
// @namespace   ShowPassword
// @description Double click to switch password field: YELLOW (pop up tooltip with password); BULE (mouse over to show password); NORMAL (hide password);
// @include     *
// @version     2015.10.11.05
// @author      OscarKoo
// @grant       none
// @run-at      document-end
// ==/UserScript==

(function(document) {
    var delay = 333;

    var index = 0;
    var getCacheKey = function(target) {
        var key = 'data-okspId';
        var value;
        if (!(value = target.getAttribute(key))) {
            target.setAttribute(key, (value = target.id || target.name || ++index));
        }
        return 'okShowPasswordMode_' + value;
    };

    var getMode = function(target) {
        var mode = localStorage.getItem(getCacheKey(target));
        if (!mode || !(mode = parseInt(mode, 10)) || mode < 1 || mode > 3)
            mode = 1;
        return mode;
    };

    var setMode = function(target, mode) {
        if (!(mode = parseInt(mode, 10)) || mode < 1 || mode > 3)
            mode = 1;
        localStorage.setItem(getCacheKey(target), mode);
        return mode;
    };

    function onInput(e) {
        var target = e.target;
        target.title = target.value;
        return false;
    }

    function onMouseOver(e) {
        var target = e.target;
        target.type = 'text';
        target.focus();
        target.selectionStart = target.selectionEnd = target.value.length;
        return false;
    }

    function onMouseOut(e) {
        var target = e.target;
        setTimeout(function() {
            target.blur();
            target.type = 'password';
        }, delay);
        return false;
    }

    function switchMode(target, mode, isClick) {
        target.title = '';
        target.type = 'password';
        target.style.border = '';
        target.removeEventListener('input', onInput);
        target.removeEventListener('mouseover', onMouseOver);
        target.removeEventListener('mouseout', onMouseOut);
        switch (mode) {
            case 1:
                target.style.border = '2px solid #FFCC00';
                target.addEventListener('input', onInput);
                target.title = target.value;
                break;
            case 2:
                target.style.border = '2px solid #3399FF';
                target.addEventListener('mouseover', onMouseOver);
                target.addEventListener('mouseout', onMouseOut);
                if (isClick) target.type = 'text';
                else target.blur();
                break;
        }
    }

    function onDblClick(e) {
        var target = e.target;
        var mode = getMode(target);
        mode = setMode(target, ++mode);
        switchMode(target, mode, true);
    }

    (function() {
        var pwdList = document.querySelectorAll('input[type=password]');
        for (var i = 0; i < pwdList.length; i++) {
            var target = pwdList[i];
            target.addEventListener('dblclick', onDblClick);
            var mode = getMode(target);
            setMode(target, mode);
            switchMode(target, mode);
        }
    })();
})(document);