XMLHTTPRequest - 测试连接而不是 .send(null) 失败 [英] XMLHTTPRequest - Test for Connection instead of .send(null) failure

问题描述

    var xml = null;
    xml = new XMLHttpRequest();
    xml.open("get", who, false);
            xml.send(null);
    if ((xml.status >= 200 && xml.status <= 300) || xml.status == 304) {
    var hi = xml.responseText;
    } else {
    alert("No Internet Connection! You will have to enter information by hand");
    };

我想设置这个警报，如果没有互联网连接，它会这样说.但是，浏览器在 xml.send(null) 处停止/挂起，并带有 NS_ERROR_FAILURE:Failure.如何为连接正确设置测试?

I want set up this alert where if there is no internet connection, it will say so. However, the browser stops/hangs at xml.send(null) with NS_ERROR_FAILURE:Failure. How can set up the test properly for a connection?

推荐答案

试试这个.

function check() {
    var z, xml = null;
    xml = new XMLHttpRequest();
    xml.open("get", who, false);
    try {
        xml.send(null);
    } catch(z) {
        alert("Network failure");
        return;
    }
    if ((xml.status >= 200 && xml.status <= 300) || xml.status == 304) {
        var hi = xml.responseText;
    } else {
        alert("No Internet Connection! You will have to enter information by hand");
    }
}

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