animate html canvas how to set Screen zoom with Javascript

[#1]

I have made an AnimateCC HTML Canvas with input Elements. On Smartphone by clicking inside an input Element the Document is zoomed in. How can I zoom out with Javascript to see the complete canvas Element on the screen of the smartphone? In other words how can I scale the canas Element with Javascript. I put the Javascript in the first Frame.

[#2]

I have made an AnimateCC HTML Canvas with input Elements. On Smartphone by clicking inside an input Element the Document is zoomed in. How can I zoom out with Javascript to see the complete canvas Element on the screen of the smartphone? In other words how can I scale the canas Element with Javascript. I put the Javascript in the first Frame.

[#3]

Your question is confusingly phrased. Do you want to zoom in then zoom back out, or do you want to not zoom at all?

[#4]

Excuse my bad english.

Take a look at this example on a smartphone I hope this will show the problem

https://www.on-design.de/test/franz/win7.html

There are input Fields, when you play the game. The smartphones zooms in as soon as the focus is in the input field. Even though I have put a big font-size for the input field. A big font-size is the normal procedure for stopping that zooming. But this does not work  for Animate CC (Jquery) input components.

So thats the problem. So As I cant stop this automatic zooming. I am looking for a command to zoom out after the user has put some text in the input field, or after he has clicked a button.

[#5 · Accepted solution]

Browser zoom is a user agent setting and therefore cannot be changed with JavaScript.

What you can do is add a viewport meta tag to prevent the browser from scaling the page.

https://developer.mozilla.org/en-US/docs/Mozilla/Mobile/Viewport_meta_tag