harmony 鸿蒙Web Subsystem ChangeLog

2025-06-12
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Web Subsystem ChangeLog

cl.web.1 Enabling Rule Change for the Viewport meta Tag

Access Level

Public

Reason for Change

In previous versions, the viewport <meta> tag is enabled or disabled based on the device type. On mobile devices, the tag is enabled, and pages are displayed with a mobile-optimized viewport. On other devices, the tag is disabled, and pages are displayed with a desktop-optimized viewport. This means that the viewport cannot be customized.

Change Impact

The setCustomUserAgent API can be used to customize the viewport. Specifically, if the custom user agent does not contain the Mobile field, the device is identified as desktop and the viewport <meta> tag is disabled by default; if the custom user agent contains the Mobile field, the device is identified as mobile and and the viewport <meta> tag is enabled by default.

This change is a non-compatible change. If the custom user agent is not standards compliant, a web page layout error will occur.

API Level

Change Since

OpenHarmony SDK 4.1.3.5

Key API/Component Changes

setCustomUserAgent

Adaptation Guide

Set a standards compliant custom user agent or use the default user agent. You are advised to use getUserAgent to obtain the default user agent and then define a custom user agent based on the default one.