web applications - Can't disable pinch zoom (and double tap) zooming on a web app in iOS Safai -

i trying disable pinch-zoom on web app, following meta-tag having 0 effect in ios safari , ios chrome:

<meta name="viewport" content="user-scalable=no, initial-scale=1.0, maximum-scale=1.0"/> 

i tried adding following meta tag, i'm having no success there either. pinch (and double-tap) zooming still enabled.

<meta name="viewport" content="user-scalable=no, initial-scale=1, maximum-scale=1, minimum-scale=1, width=device-width, height=device-height, target-densitydpi=device-dpi" /> 

any insight why 2 meta tags might not working?

for me following meta tags working in both scenarios

this works proper cordova/ionic project disable double tap/pinch on normal page

<meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no, width=device-width"> 

i open simple page using jquery/bootstrap in ios safari, disable double tap/pinch zoom

<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"> 

you may check codes if have not tried : https://stackoverflow.com/a/11689448/4557505

also please provide details web app default web app html5/responsive or using cross platform cordova/ionic, in checking specific scenario