Window.sessionStorage

在此页

句法
范例
规范
浏览器兼容性
另请参阅
相关话题

只读 sessionStorage property accesses a session 存储 object for the current origin . sessionStorage 类似于 localStorage ; the difference is that while data in localStorage doesn't expire, data in sessionStorage is cleared when the page session ends.

A page session lasts as long as the browser is open, and survives over page reloads and restores.
Opening a page in a new tab or window creates a new session with the value of the top-level browsing context, which differs from how session cookies work.
Opening multiple tabs/windows with the same URL creates sessionStorage for each tab/window.
Closing a tab/window ends the session and clears objects in sessionStorage .

Data stored in sessionStorage is specific to the protocol of the page . In particular, data stored by a script on a site accessed with HTTP (e.g., http://example.com ) is put in a different sessionStorage object from the same site accessed with HTTPS (e.g., https://example.com ).

The keys and the values are always in the UTF-16 DOMString format, which uses two bytes per character. As with objects, integer keys are automatically converted to strings.

句法

myStorage = window.sessionStorage;

值

A 存储 object which can be used to access the current origin's session storage space.

异常

SecurityError: The request violates a policy decision, or the origin is not a valid scheme/host/port tuple (this can happen if the origin uses the 文件： or data: scheme, for example). For example, the user may have their browser configured to deny permission to persist data for the specified origin.

范例

The following snippet accesses the current origin's session 存储 object and adds data to it with Storage.setItem() .

sessionStorage.setItem('myCat', 'Tom');

The following example autosaves the contents of a text field, and if the browser is refreshed, restores the text field content so that no writing is lost.

// Get the text field that we're going to track
let field = document.getElementById("field");
// See if we have an autosave value
// (this will only happen if the page is accidentally refreshed)
if (sessionStorage.getItem("autosave")) {
  // Restore the contents of the text field
  field.value = sessionStorage.getItem("autosave");
}
// Listen for changes in the text field
field.addEventListener("change", function() {
  // And save the results into the session storage object
  sessionStorage.setItem("autosave", field.value);
});

注意 : Please refer to the 使用 Web 存储 API article for a full example.

规范

规范	状态	注释
HTML 实时标准 The definition of 'sessionStorage' in that specification.	实时标准

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
`sessionStorage`	Chrome 5	Edge 12	Firefox 2	IE 8	Opera 10.5	Safari 4	WebView Android ≤37	Chrome Android 18	Firefox Android 4	Opera Android 11	Safari iOS 3.2	Samsung Internet Android 1.0

在此页

句法

值

异常

范例

规范

浏览器兼容性

图例

另请参阅

元数据

相关话题