在此页

• 特性
• 事件
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

这是 实验性技术
检查 浏览器兼容性表格 要小心谨慎在生产中使用这之前。

VisualViewport interface of the Visual Viewport API represents the visual viewport for a given window. For a page containing iframes, each iframe, as well as the containing page, will have a unique window object. Each window on a page will have a unique VisualViewport representing the properties associated with that window.

You can get a window's visual viewport using Window.visualViewport .

注意 : Only the top-level window has a visual viewport that's distinct from the layout viewport. Therefore, it's generally only the VisualViewport object of the top-level window that's useful. For an <iframe> , visual viewport metrics like VisualViewport.width always correspond to layout viewport metrics like document.documentElement.clientWidth .

特性

VisualViewport also inherits properties from its parent, EventTarget .

VisualViewport.offsetLeft 只读

Returns the offset of the left edge of the visual viewport from the left edge of the layout viewport in CSS pixels.

VisualViewport.offsetTop 只读

Returns the offset of the top edge of the visual viewport from the top edge of the layout viewport in CSS pixels.

VisualViewport.pageLeft 只读

Returns the x coordinate of the visual viewport relative to the initial containing block origin of the top edge in CSS pixels.

VisualViewport.pageTop 只读

Returns the y coordinate of the visual viewport relative to the initial containing block origin of the top edge in CSS pixels.

VisualViewport.width 只读

Returns the width of the visual viewport in CSS pixels.

VisualViewport.height 只读

Returns the height of the visual viewport in CSS pixels.

VisualViewport.scale 只读

Returns the pinch-zoom scaling factor applied to the visual viewport.

事件

监听这些事件使用 addEventListener() or by assigning an event listener to the relevant on eventname 特性为此接口。

resize

Fired when the visual viewport is resized.
也可用凭借 VisualViewport.onresize 特性。

scroll

Fired when the visual viewport is scrolled.
也可用凭借 VisualViewport.onscroll 特性。

范例

Hiding an overlaid box on zoom

This example, taken from the Visual Viewport README , shows how to write a simple bit of code that will hide an overlaid box (which might contain an advert, say) when the user zooms in. This is a nice way to improve the user experience when zooming in on pages. A live sample is also available.

var bottomBar = document.getElementById('bottombar');
var viewport = window.visualViewport;
function resizeHandler() {
   if (viewport.scale > 1.3)
     bottomBar.style.display = "none";
   else
     bottomBar.style.display = "block";
}
window.visualViewport.addEventListener('resize', resizeHandler);
					

Simulating position: device-fixed

This example, also taken from the Visual Viewport README , shows how to use this API to simulate position: device-fixed , which fixes elements to the visual viewport. A live sample is also available.

var bottomBar = document.getElementById('bottombar');
var viewport = window.visualViewport;
function viewportHandler() {
  var layoutViewport = document.getElementById('layoutViewport');
  // Since the bar is position: fixed we need to offset it by the visual
  // viewport's offset from the layout viewport origin.
  var offsetLeft = viewport.offsetLeft;
  var offsetTop = viewport.height
              - layoutViewport.getBoundingClientRect().height
              + viewport.offsetTop;
  // You could also do this by setting style.left and style.top if you
  // use width: 100% instead.
  bottomBar.style.transform = 'translate(' +
                              offsetLeft + 'px,' +
                              offsetTop + 'px) ' +
                              'scale(' + 1/viewport.scale + ')'
}
window.visualViewport.addEventListener('scroll', viewportHandler);
window.visualViewport.addEventListener('resize', viewportHandler);
					

注意 : This technique should be used with care; emulating position: device-fixed in this way can result in the fixed element flickering during scrolling.

规范

规范	状态	注释
Visual Viewport API The definition of 'VisualViewport' in that specification.	草案	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
VisualViewport	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
height	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
offsetLeft	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
offsetTop	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
onresize	Chrome 62 62 部分支持 61	Edge 79	Firefox 66	IE No	Opera 49 49 部分支持 48	Safari 13	WebView Android 62 62 部分支持 61	Chrome Android 62 62 部分支持 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 46 46 部分支持 45	Safari iOS 13	Samsung Internet Android 8.0 8.0 部分支持 8.0
onscroll	Chrome 62 62 部分支持 61	Edge 79	Firefox 66	IE No	Opera 49 49 部分支持 48	Safari 13	WebView Android 62 62 部分支持 61	Chrome Android 62 62 部分支持 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 46 46 部分支持 45	Safari iOS 13	Samsung Internet Android 8.0 8.0 部分支持 8.0
pageLeft	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
pageTop	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
resize event	Chrome 62 62 部分支持 61	Edge 79	Firefox 66	IE No	Opera 49 49 部分支持 48	Safari 13	WebView Android 62 62 部分支持 61	Chrome Android 62 62 部分支持 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 46 46 部分支持 45	Safari iOS 13	Samsung Internet Android 8.0 8.0 部分支持 8.0
scale	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0
scroll event	Chrome 62 62 部分支持 61	Edge 79	Firefox 66	IE No	Opera 49 49 部分支持 48	Safari 13	WebView Android 62 62 部分支持 61	Chrome Android 62 62 部分支持 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 46 46 部分支持 45	Safari iOS 13	Samsung Internet Android 8.0 8.0 部分支持 8.0
width	Chrome 61	Edge 79	Firefox 63	IE No	Opera 48	Safari 13	WebView Android 61	Chrome Android 61	Firefox Android 68 68 Disabled ). To change preferences in Firefox, visit	Opera Android 45	Safari iOS 13	Samsung Internet Android 8.0

图例

完整支持

完整支持

不支持

不支持

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

用户必须明确启用此特征。

用户必须明确启用此特征。

另请参阅

• Web Viewports Explainer — useful explanation of web viewports concepts, including the difference between visual viewport and layout viewport.

元数据

• 最后修改： May 2, 2020

相关话题

1. Visual Viewport API
2. VisualViewport
3. 特性

   1. height
   2. offsetleft
   3. offsetTop
   4. pageLeft
   5. pageTop
   6. scale
   7. width
4. 事件

   1. onresize
   2. onscroll
5. Related pages for Visual Viewport

   1. Window.visualViewport