How to set fix zoom level or scale back in webview?

Zoom works without any pro开发者_C百科blem, but if I select any input field the webview zooms in automatically.

How do I can prevent this zoom behavior?

• set fix zoom level?
• scale back to previous zoom level?

Not sure about Android webkit, but this works on iOS webkit:

input[type='text'],textarea {font-size:1em;}