Method one:
Insert (copy, paste) following CSS code in your Blogger template to disable the Blogger Navbar
<style type="text/css">
#b-navbar {
height:0px;
visibility:hidden;
display:none
}
</style>
Method two
This is another simple way to remove the Blogger Navbar but it will not form valid HTML. Replace your <body> tag with the following code and hide will hide the Blogger navbar.
<noscript><body></noscript>
I prefer the first method. I have applied it only twice by now.
