当前活动历史项(history entry)改变会触发popstate事件。调用history.pushState()创建新的历史项(history entry)，或调用history.replaceState()替换新的历史项(history entry)，那么popstate事件的state属性会包含历史项(history entry)状态对象(state object)的拷贝。
需要注意的是调用history.pushState()或history.replaceState()不会触发popstate事件。只有在做出浏览器动作时，才会触发该事件，如用户点击浏览器的回退按钮（或者在Javascript代码中调用history.back()）
不同的浏览器在加载页面时处理popstate事件的形式存在差异。页面加载时Chrome和Safari通常会触发(emit )popstate事件，但Firefox则不会。
常规信息
- Specification
- HTML5
- Interface
- PopStateEvent
- Bubbles
- 是
- Cancelable
- 否
- Target
- defaultView
- Default Action
- 无
属性
| Property | Type | Description |
|---|---|---|
target 只读 |
EventTarget |
浏览上下文 (<code>window</code>). |
type 只读 |
DOMString |
The type of event. |
bubbles 只读 |
boolean |
Does the event normally bubble? |
cancelable 只读 |
boolean |
Is it possible to cancel the event? |
state 只读 |
any | The current history entry's state object (if any). |
浏览器兼容性
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | Yes | 4.0 (2) | 10.0 | Yes | limited |
| Feature | Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Basic support | 3.0 (buggy in 2.2 and 2.3) | 4.0 (2) | 10.0 | Yes | limited |
示例
打开https://example.com/example.html页面运行以下代码， 会按预期那样弹出alert提示。
window.onpopstate = function(event) {
alert("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
history.pushState({page: 1}, "title 1", "?page=1");
history.pushState({page: 2}, "title 2", "?page=2");
history.replaceState({page: 3}, "title 3", "?page=3");
history.back(); // alerts "location: https://example.com/example.html?page=1, state: {"page":1}"
history.back(); // alerts "location: https://example.com/example.html, state: null
history.go(2); // alerts "location: https://example.com/example.html?page=3, state: {"page":3}
注意，虽然原始的历史项（ https://example.com/example.html所对应的）没有关联的状态对象（state object），但稍后调用history.back()激活该历史项时，仍会触发popstate事件。