TypeError: canvas.save is not a function canvas.save();_html/css_WEB-ITnose

For example:
Firefox shows that canvas.save() cannot be used?
Why is this!

Reply to discussion (solution)

What version of ff do you have? How did you write your code?
I tested the ff37 version and there is no problem
Example
http://www.tutorialspoint.com/html5/canvas_states.htm

Thank you! I wrote it wrong, not canvas