问题
The issue is mobile browsers will zoom in an input field or select drop-down on focus. I've looked into different solutions and so far the most elegant I found does it with setting a font-size of an input field to 16px. This works fine on a standalone input field but if you have a parent container which incorporates a button, after changing font-size to 16px will make a bit of a gap under the button.
Another solution would be to set a default font-size for input fields to 16px and adjust a button size correctly.
Setting a font-size to 16px doesn't prevent select drop-downs from zooming though.
回答1:
You can do it this way:
<meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1">
来源：https://stackoverflow.com/questions/24310074/disable-input-auto-zooming-on-mobile-devices