Mike

As a logged in user, you can already control the visibility of the WordPress Toolbar when modifying your profile with the ‘Show Toolbar when viewing site’ option. This plugin lets you manage that option while viewing the public part of the site without visiting your profile page saving you a few steps. A few steps over the course of a year can be a considerable saving.
To use, add the following to the end of your URL location:
<ul>
<li>?hidebar or ?nobar to hide the Toolbar</li>
<li>?showbar or ?yesbar to show the Toolbar</li>
</ul>
If you have a ? in the URL already, swap it with a &
This plugin differentiates itself by having a zero footprint. It does not leave any visible buttons, add any extra javascripts or CSS styles. It is also WordPress Network compatible – that is, you can enable it network wide.
Collaborate, participate, or fork this plugin on <a href="https://github.com/zedzedzed/toggle-toolbar" rel="nofollow ugc">Github</a>.

Toggle Toolbar

Easily toggle the WordPress Toolbar by adding commands to the end of your URL while logged in.

Jeremy Saxey

Easily hide or show the front-end WordPress Admin Toolbar with a click of a button. The plugin adds a special button to the right side of the WordPress Admin Toolbar that only displays when you are outside the admin area of WordPress on the front-end. Clicking it will make the admin bar slide off the page to the top left corner, leaving only the hide/show button visible. Clicking the button again will restore the Toolbar to its original position. The shown/hidden position is remembered between page visits so that it can be kept hidden away until you are ready to bring it back.
There are no options or configuration. Just install and activate the plugin. When you exit the admin area, you will see the button to the far right of the Toolbar.
I actually like the WordPress Toolbar. It’s a convenient way to go back and forth from the admin area to the public website. However, when I’m doing design modifications for a theme, the Toolbar can be visually distracting. I wanted a quick way to hide the WordPress Toolbar when needed, but otherwise keep it around. I tried several plugins but they didn’t work as I wanted or didn’t even work at all in some cases. So I decided to build my own.
<h4>Contributions Welcome</h4>
This plugin is on Github. <a href="https://github.com/jr00ck/hide-wp-toolbar" rel="nofollow ugc">Submit a pull request</a> if you’d like to contribute.

Hide WP Toolbar

I had tried several plugins that this was the one that has the toogle feature that I love

Unique

Easily hide or show the front-end WordPress Admin Toolbar with a click of a button.

Toggle Toolbar vs Hide WP Toolbar