JavaScript跳过document.write去window.prompt？

Question

这段代码本应在 window.prompt() 和 document.write() 之间来回切换，但它会遍历所有 window.prompt() 消息并迭代必须这样做，然后它会在 while 循环的出口处转储所有 document.write 输出。来回可以做什么？

<!DOCTYPE HTML>
    <html>
    <head>
        <meta charset="utf-8">
        <title>gasMilage</title>
        <script type = "text/javascript">

            var gasNow;
            var distanceNow;
            var mpgNow;
            var gasOverall;
            var distanceOverall;
            var mpgOverall;
            var answer;

            answer = "yes";

            gasOverall = parseInt(0);
            distanceOverall = parseInt(0);

            while(answer == "yes"){

            gasNow = window.prompt(
            "Enter the gallons of gas used: ")
            gasNow = parseInt(gasNow);

            distanceNow = window.prompt(
            "Enter the distance traveled in miles: ")
            distanceNow = parseInt(distanceNow);

            mpgNow = parseInt(distanceNow / gasNow);

            document.writeln(
            "Your current mpg is " + mpgNow + "<br />");

            gasOverall = gasNow + gasOverall;
            distanceOverall = distanceNow + distanceOverall;
            mpgOverall = parseInt(distanceOverall/gasOverall);

            document.writeln(
            "Your overall mpg is " + mpgOverall + "<br />");

            answer = window.prompt(
            "If you want to add more values, type yes.")
            }

        </script>    
    </head>
    <body>
    </body>
</html>

Answer 1

是的，这是因为提示出现得太快，DOM 没有时间写，因为有一个待处理的提示请求正在进行。解决方案是在您的提示方法上设置超时。

但是因为你在这里做了一个 while 循环，它会再次做第一个提示而不用等待超时。因此，与其使用 while 循环，不如将其包装在一个函数中，如果最后一个提示为是，则递归调用它。

试试这个 fiddle

(function query() {
    gasNow = window.prompt(
    "Enter the gallons of gas used: ")
    gasNow = parseInt(gasNow);

    distanceNow = window.prompt(
    "Enter the distance traveled in miles: ")
    distanceNow = parseInt(distanceNow);

    mpgNow = parseInt(distanceNow / gasNow);

    document.writeln(
    "Your current mpg is " + mpgNow + "<br />");

    gasOverall = gasNow + gasOverall;
    distanceOverall = distanceNow + distanceOverall;
    mpgOverall = parseInt(distanceOverall/gasOverall);

    document.writeln(
    "Your overall mpg is " + mpgOverall + "<br />");

    setTimeout(() => {
        answer = window.prompt(
        "If you want to add more values, type yes.")
        if(answer === 'yes') query();
    }, 1);

})()

Answer 2

在每个 document.write 之后您可以添加一个延迟。这将为呈现文档留出时间。

JavaScript跳过document.write去window.prompt？

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