>I have a strange situation. I found a Fiddle that has an example of Bootstrap 3 Collapse menu. The menu that collapses into a button when the browser gets to the mobile size. And then by clicking on the button the menu is opened. When I run this code in the Fiddle, it works. This is the Fiddle:
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>http://jsfiddle.net/9pruK/
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>But when I created a test.html with exactly the code from this fiddle it does not work. That is, in my test.html the button is created but clicking on the button does not produce the menu. I have compared the Bootstrap.css in the Fiddle and the one I use and it is the same (the size is exactly the same). What can be causing my test.html not to work?

I'm using a similar menu layout and it works as advertised :-]
Can you post your html (I know you say it's *exactly* the same but .....)
And are you using the same browser with your html as when running the Fiddle example ?