Question

我正在尝试使用XMLHttpRequest从另一个页面获取值，我发现只有在以下脚本中关闭所有警报后才会获取该值：

function changePw_prompt() {
    var success = false;
    while(!success) {
        var newPassword = prompt("Please enter a new password", "");
        if (newPassword != null) {
            replyMsg = sendPassword(newPassword);
            if (replyMsg == "CHNGSUCC") {
                alert("Password changed");
                sucess = true;
            } else if (replyMsg == "CHNGFAIL") {
                alert("Error: Password is shorter than 8 characters.");
                sucess = false;
            } else if (replyMsg == "CHNGERROR") {
                alert("Internal error, please contact server admin.");
                sucess = true;
            }
        } else {
            alert("Password unchanged");
            success = true;
        }
    }

}

function sendPassword(pwd) {
    alert("Run 2nd function");
    var xmlhttp2 = new XMLHttpRequest();
    xmlhttp2.onreadystatechange = function() {
        if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
            var reply2 = xmlhttp2.responseText;
            alert(reply2);
            return reply2;
        }
    }
    xmlhttp2.open("POST","changepw.php",true);
    xmlhttp2.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    xmlhttp2.send("uid="+document.getElementById("amsnr").value+"&pwd="+pwd);   
}

我想知道这里有什么问题。另外，如果我想为replyMsg变量返回正确的值，我应该如何更改我的代码，该变量从另一个页面获取响应。

感谢。

已更新我修改了我的代码以使其更简单，但它仍然无效，代码如下，我应该如何修改它以使用回调函数保持我的原始用途？

function changePw_prompt() {
    var success = false;
    while(!success) {
        var replyMsg = "";
        var newPassword = prompt("Please enter a new password", "");
        if (newPassword != null) {
            var xmlhttp2 = new XMLHttpRequest();
            xmlhttp2.onreadystatechange = function() {
                if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
                    var replyMsg = xmlhttp2.responseText;
                    alert(replyMsg);
                    if (replyMsg == "CHNGSUCC") {
                        alert("Password changed");
                        sucess = true;
                    } else if (replyMsg == "CHNGFAIL") {
                        alert("Error: Password is shorter than 8 characters.");
                        sucess = false;
                    } else if (replyMsg == "CHNGERROR") {
                        alert("Internal error, please contact server admin.");
                        sucess = true;
                    }   
                }
            }
            xmlhttp2.open("POST","changepw.php",true);
            xmlhttp2.setRequestHeader("Content-type","application/x-www-form-urlencoded");
            xmlhttp2.send("uid="+document.getElementById("amsnr").value+"&pwd="+newPassword);

        } else {
            alert("Password unchanged");
            success = true;
        }
    }

}

Answer 1

示例：

/**
 * Call Example
 * changePw_prompt(function(changed) { console.log("password changed? ", changed); })
 */
/**
 * @param function continueCallback : will run with the argument false/true 
 */
function changePw_prompt(continueCallback) {
    var newPassword = prompt("Please enter a new password", "");
    if (newPassword == null) {
            alert("Password unchanged");
            continueCallback(false);
    } else {
            var xmlhttp2 = new XMLHttpRequest();
            xmlhttp2.onreadystatechange = function() {
                if (xmlhttp2.readyState == 4 && xmlhttp2.status == 200) {
                    var replyMsg = xmlhttp2.responseText;
                    alert(replyMsg);
                    if (replyMsg == "CHNGSUCC") {
                        alert("Password changed");
                        continueCallback(true);
                    } else if (replyMsg == "CHNGFAIL") {
                        alert("Error: Password is shorter than 8 characters.");

                        // repeat the process
                        changePw_prompt(continueCallback);
                    } else if (replyMsg == "CHNGERROR") {
                        alert("Internal error, please contact server admin.");
                        continueCallback(false);
                    }
                }
            }
            xmlhttp2.open("POST","changepw.php",true);
            xmlhttp2.setRequestHeader("Content-type","application/x-www-form-urlencoded");
            var uid = encodeURIComponent(document.getElementById("amsnr").value);
            var pwd = encodeURIComponent(newPassword);
            xmlhttp2.send("uid="+uid+"&pwd="+pwd);
    }
}

XMLHttpRequest在关闭所有警报之前不提取值

1 个答案: