javascript - 函数没有被调用

Question

我的 play() 函数没有被调用。我真的不知道为什么。

我有以下代码:

var mp = document.getElementById("mp3");
   function play() {
   mp.play();
   console.log("hello");
}

function scan() {
  cordova.plugins.barcodeScanner.scan(
    function(result) {
      if (result.text == "home") {
        var atHomeRepQR = '<div class="container-h"><div class="card"><div class="item item-text-wrap "><i class="icon ion-unlocked"></i> Diese Ansicht ist entsperrt.</div></div><button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>';
        save("atHomeSaveQR", atHomeRepQR);
      }
      if (result.text == "street") {
        var atStreetRepQR = '<div class="container-s"><div class="card"><div class="item item-text-wrap "><i class="icon ion-unlocked"></i> Diese Ansicht ist entsperrt.</div></div><button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>';
        save("atStreetSaveQR", atStreetRepQR);
      }
      if (result.text == "bern") {
        var atBernRepQR = '<div class="container-b"><div class="card"><div class="item item-text-wrap "><i class="icon ion-unlocked"></i> Diese Ansicht ist entsperrt.</div></div><button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>';
        save("atBernSaveQR", atBernRepQR);
      }
      if (result.text == "bahnhof") {
        var atBahnhofRepQR = '<div class="container-ba"><div class="card"><div class="item item-text-wrap "><i class="icon ion-unlocked"></i> Diese Ansicht ist entsperrt.</div></div><button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>';
        save("atBahnhofSaveQR", atBahnhofRepQR);
      }
      if (result.text == "atelier") {
        var atAtelierRepQR = '<div class="container-at"><div class="card"><div class="item item-text-wrap "><i class="icon ion-unlocked"></i> Diese Ansicht ist entsperrt.</div></div><button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>';
        save("atAtelierSaveQR", atAtelierRepQR);
      }

    },
    function(error) {
      alert("Scanning failed: " + error);
    }
  );
}

语法

<button onclick="play()" class="button button-positive btn">Play</button></div><audio id="mp3"><source src="video/ping.mp3" type="audio/mpeg"></audio>

当你问我时是正确的。

我的错误是什么？

Answer 1

您的 mp 变量可能在 #mp3 被解析之前被初始化。您应该将任何类似的静态代码包装在 document.ready block 中，以便其执行被推迟到页面加载完成。

理想情况下，这将使用 jQuery 实现:

var mp;
$(document).ready(function() {
    mp = document.getElementById("mp3");
});

如果没有它，这对大多数现代浏览器来说就足够了(参见 this answer ):

var mp;
document.addEventListener("DOMContentLoaded", function(event) { 
    mp = document.getElementById("mp3");
});