Add code to the userChrome.css file below the default @namespace line.

• http://kb.mozillazine.org/userChrome.css

The customization files userChrome.css (interface) and userContent.css (websites) are located in the chrome folder in the user profile folder.

• http://kb.mozillazine.org/Editing_configuration

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

*|*.textbox-input:-moz-placeholder { color:transparent !important; }
*|*.textbox-input:-moz-placeholder:hover { color:graytext !important; }

Use this in Firefox 19+:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

*|*.textbox-input::-moz-placeholder { color:transparent !important; }
*|*.textbox-input:hover::-moz-placeholder { color:black !important; }

Thank you. Worked fine. For anyone who comes across this in the future, change "graytext" to "transparent" to hide the placeholder all the time. As is above, the placeholder shows when the mouse points at the box.

I can't find a userchrome.css file on my computer. I did find a userChrome-example file, and modified it as described. I don't know where to save it. Where is it located?

I went to c:\program files(x86)\Mozilla Firefox. I have he following folders

components, defaults, dictionaries, extensions, install, plugins, searchplugins, and uninstall.

I could of course rename the file, but don't know where to save it.

That is not the proper location of the Firefox Profile Folder.

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder
• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\

The "AppData" folder is a hidden folder.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

You need to create the chrome folder and userChrome.css in the profile folder if they do not exist.