如果 XMLHttpRequest 对象支持 W3C 进度事件，如何检查 JavaScript? [英] How to check in JavaScript if XMLHttpRequest object supports W3C Progress Events?

问题描述

如果 XMLHttpRequest 对象支持 W3C 进展事件?我的意思是如果将 onload、onprogress、onabort、onerror 等属性设置为某些处理函数如上所述，那些函数调用了这些事件.

Is there any way to check within JavaScript if XMLHttpRequest object supports W3C Progress Events? I mean here if setting onload, onprogress, onabort, onerror, etc. properties to some handler function would have those function called those events, as described.

附加(额外)问题:有没有办法增加 XMLHttpRequest(例如使用一些计时器)来支持这些事件?

Additional (bonus) question: is there a way to augment XMLHttpRequest (e.g. using some timers) to support those events?

旁注:我首先在 XMLHttpRequest 这里

推荐答案

你试过这样吗?

try {
    var xhr = new XMLHttpRequest();

    if ('onprogress' in xhr) {
        // Browser supports W3C Progress Events
    } else {
        // Browser does not support W3C Progress Events
    }
} catch (e) {
    // Browser is IE6 or 7
}

我在 Firefox &IE8.Firefox 显示它支持它.IE 表示它不支持 W3C Progress 事件.

I tested this in Firefox & IE8. Firefox shows it supports it. IE says it has no support for W3C Progress events.

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