当程序开始加载时，loadstart 事件将被触发。这个事件可以被 XMLHttpRequest 调用, 也适用于 <img> 和 <video> 元素.
基本信息
- 规范文档
- Progress
- 接口
- ProgressEvent
- 冒泡
- No
- 可取消
- No
- 目标
- Element
- 默认动作
- None
属性
| Property | Type | Description |
|---|---|---|
target 只读 |
EventTarget |
The event target (the topmost target in the DOM tree). |
type 只读 |
DOMString |
The type of event. |
bubbles 只读 |
Boolean |
Whether the event normally bubbles or not |
cancelable 只读 |
Boolean |
Whether the event is cancellable or not? |
lengthComputable |
boolean | Specifies whether or not the total size of the transfer is known. Read only. |
loaded |
unsigned long (long) | The number of bytes transferred since the beginning of the operation. This doesn't include headers and other overhead, but only the content itself. Read only. |
total |
unsigned long (long) | The total number of bytes of content that will be transferred during the operation. If the total size is unknown, this value is zero. Read only. |