JavaScript:循环中的setTimeout仍然不起作用

Question

JavaScript:循环中的setTimeout仍然不起作用

Fil*_* CZ 0 javascript while-loop settimeout

我需要创建一个脚本,它将发送请求(数组中的数据)连续发送到服务器并获得响应,但我还需要在每第5或第6次迭代之间进行延迟(大约3-5秒).例如:

1st data
2nd data
3rd data
4th data
5th data
** 5sec. delay - wait here**
6th data
7th data
...etc...

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发送和接收数据没问题,但是我无法在我的代码中正确实现setTimeout以便完全按照我的需要工作.

非常感谢大家,他们将能够修复此代码.

<!DOCTYPE html>
<html>
<body>

<h2>AJAX</h2>

<button type="button" onclick="loadDoc()">Request data</button>

<p id="demo"></p>

<script>
function loadDoc() {
    var xhttp = [];



    var code = [
"WOICEL0Q9P",
"ZJTS4GYJEJ",
"HJPMQOCX31",
"MP26N0BH01",
"7TJNYZIRJR",
"Z5MIDDG4N2",
"BX6MKYK0O7",
"KVFVH1ESQX",
"40ADY3ZBE5",
"V4NT360JR5",
"FDI8AFL680",
"ZH89N59XQR",
"M6OS2OX38H",
"D8O76YDLM0",
"86GBMJLIXY",
"1QRFVU26VK",
"HFUI9QV6DY",
"VN83OGR825",
"DDMPCBX2MF",
"2M3QFPI234"
    ];

    var i = code.length;
    var j = code.length;
    var k = 5000;

    var p = 0;


    while (i--) {
        var process = (function(i) {
            if (p == 5) {
                p = 0;
                function func(i) {
                    xhttp[i] = new XMLHttpRequest();
                    xhttp[i].onreadystatechange = function() {
                        if (xhttp[i].readyState == 4 && xhttp[i].status == 200) {
                            if (i == j) {
                                document.getElementById("demo").innerHTML = code[i] + ":   " + xhttp[i].responseText;
                            }
                            else {
                                document.getElementById("demo").innerHTML += "<br><br>" + code[i] + ":   " + xhttp[i].responseText;
                            }
                        }
                    };
                    xhttp[i].open("POST", "https://www.example.com/services/postdata.svc", true);
                    xhttp[i].setRequestHeader("Host", "www.example.com");
                    xhttp[i].setRequestHeader("Accept", "application/json, text/javascript");
                    xhttp[i].setRequestHeader("Accept-Language", "cs,en-US;q=0.7,en;q=0.3");
                    xhttp[i].setRequestHeader("Accept-Encoding", "gzip, deflate, br");
                    xhttp[i].setRequestHeader("Content-Type", "application/json; charset=utf-8");
                    xhttp[i].setRequestHeader("Cache-Control", "no-cache");
                    xhttp[i].setRequestHeader("X-Requested-With", "XMLHttpRequest");
                    xhttp[i].setRequestHeader("Referer", "https://www.example.com/postdata-test.htm");
                    xhttp[i].setRequestHeader("Content-Length", "37");
                    xhttp[i].setRequestHeader("Connection", "keep-alive");
                    xhttp[i].send('{"code":"'+code[i]+'","confirm":false}');
                    //console.log('hello - Test if delay is here');
                    p++;
                }
                setTimeout(func(i), k);
                k += 5000;
            }
            else {
                xhttp[i] = new XMLHttpRequest();
                xhttp[i].onreadystatechange = function() {
                    if (xhttp[i].readyState == 4 && xhttp[i].status == 200) {
                        if (i == j) {
                            document.getElementById("demo").innerHTML = code[i] + ":   " + xhttp[i].responseText;
                        }
                        else {
                            document.getElementById("demo").innerHTML += "<br><br>" + code[i] + ":   " + xhttp[i].responseText;
                        }
                    }
                };
                xhttp[i].open("POST", "https://www.example.com/services/postdata.svc", true);
                xhttp[i].setRequestHeader("Host", "www.example.com");
                xhttp[i].setRequestHeader("Accept", "application/json, text/javascript");
                xhttp[i].setRequestHeader("Accept-Language", "cs,en-US;q=0.7,en;q=0.3");
                xhttp[i].setRequestHeader("Accept-Encoding", "gzip, deflate, br");
                xhttp[i].setRequestHeader("Content-Type", "application/json; charset=utf-8");
                xhttp[i].setRequestHeader("Cache-Control", "no-cache");
                xhttp[i].setRequestHeader("X-Requested-With", "XMLHttpRequest");
                xhttp[i].setRequestHeader("Referer", "https://www.example.com/postdata-test.htm");
                xhttp[i].setRequestHeader("Content-Length", "37");
                xhttp[i].setRequestHeader("Connection", "keep-alive");
                xhttp[i].send('{"code":"'+code[i]+'","confirm":false}');
                p++;
            }
        })(i);
    }
}
</script>

</body>
</html>

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Answer 1

Arw*_*ett 5

你可能想使用setInterval()或者你必须recursivly调用setTimeout()

(function func() {
    //do your upload
    setTimeout(func, 3);
})();

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使用bind可以传递参数:

(function func(i) {
    //do your upload
    setTimeout(func.bind(this, i), 3);
})();

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