每n秒获取一个新值

Question

我有一个显示报价的网页。我随机选择其中一个引号。目前，每次加载网页时都会执行此操作，现在，我希望它每5秒选择一次。我是一个初学者，不确定如何最好地实现此功能或适当的功能。setInterval？，setTimeout？，delay？，wait？var quotes = JSON.parse('{\    "0": "Don\'t worry about what anybody else is going to do. The best way to predict the future is to invent it. -- Alan Kay", \    "1": "Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great. -- Mark Twain", \    "2": "No problem should ever have to be solved twice. -- Eric S. Raymond, How to become a hacker", \    "3": "Attitude is no substitute for competence. -- Eric S. Raymond, How to become a hacker", \    "4": "It is said that the real winner is the one who lives in today but able to see tomorrow. -- Juan Meng", \    "5": "Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it. -- Alan J.Perlis(Epigrams in programming)", \    "6": "A year spent in artificial intelligence is enough to make one believe in God. -- Alan J.Perlis(Epigrams in programming)" \}');function getRandomArbitrary(min, max) {    return Math.random() * (max - min) + min;}var num = Math.floor(getRandomArbitrary(0, Object.keys(quotes).length));document.getElementById('quote').innerHTML = quotes[num];如前所述，我现在希望ID中的值'quote'每5秒更新一次。所以我认为这意味着更新numvar？

Answer 1

很好的是您想出了填充div的代码，我在setInterval中添加了一个代码段来调用该代码，该代码每5s更新一次。确保移开后调用clearInterval以停止setInterval（移至其他页面，关闭）。

var quotes = JSON.parse('{\

    "0": "Don\'t worry about what anybody else is going to do. The best way to predict the future is to invent it. -- Alan Kay", \

    "1": "Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great. -- Mark Twain", \

    "2": "No problem should ever have to be solved twice. -- Eric S. Raymond, How to become a hacker", \

    "3": "Attitude is no substitute for competence. -- Eric S. Raymond, How to become a hacker", \

    "4": "It is said that the real winner is the one who lives in today but able to see tomorrow. -- Juan Meng", \

    "5": "Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it. -- Alan J.Perlis(Epigrams in programming)", \

    "6": "A year spent in artificial intelligence is enough to make one believe in God. -- Alan J.Perlis(Epigrams in programming)" \

}');

function updateUI() {

var num = Math.floor(getRandomArbitrary(0, Object.keys(quotes).length));

document.getElementById('quote').innerHTML = quotes[num];

}

function getRandomArbitrary(min, max) {

    return Math.random() * (max - min) + min;

}

var interval = setInterval(updateUI, 5000);

//cleanup

//clearInterval(interval);

<div id="quote"></div>

Answer 2

您可以使用setInterval，它以固定的时间延迟重复调用一个函数或执行一个代码段，并且回调函数内部num每次都会获取一个新值。

var quotes = JSON.parse('{\

    "0": "Don\'t worry about what anybody else is going to do. The best way to predict the future is to invent it. -- Alan Kay", \

    "1": "Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great. -- Mark Twain", \

    "2": "No problem should ever have to be solved twice. -- Eric S. Raymond, How to become a hacker", \

    "3": "Attitude is no substitute for competence. -- Eric S. Raymond, How to become a hacker", \

    "4": "It is said that the real winner is the one who lives in today but able to see tomorrow. -- Juan Meng", \

    "5": "Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it. -- Alan J.Perlis(Epigrams in programming)", \

    "6": "A year spent in artificial intelligence is enough to make one believe in God. -- Alan J.Perlis(Epigrams in programming)" \

}');

function getRandomArbitrary(min, max) {

  return Math.random() * (max - min) + min;

}

// you need this value only once so no need to get it at every interval

let maxVal =Object.keys(quotes).length);

setInterval(() => {

  var num = Math.floor(getRandomArbitrary(0,maxVal);

  document.getElementById('quote').innerHTML = quotes[num];

}, 5000)

<div id='quote'></div>