onerror 事件显示图片 - javascript

Question

我有一个 javascript 代码，它给一个页面一个 link，如果该页面不回答它就会出错，然后重试。我想收到错误消息在屏幕上显示

我在这里发现了一些关于它的问题，但无法将它们应用到我的代码中。这是我的代码，我可以在其中插入代码，以便在出现错误时使用 document.write

在屏幕上显示图像

window.setInterval(function() {
    requestURL = "https://api.spark.io/v1/devices/" + deviceID1 + "/" + getFunc + "/?access_token=" + accessToken;
    $.getJSON(requestURL, function(json) {
        var vdadosdospark=json.result;//coloca resultado do json na variavel
        var vdadosdospark=vdadosdospark.replace("-", '')//exclui caractere -
        var resultadoA = vdadosdospark.substr(9, 6);//seleciona os caracteres referentes a amperagem
        var resultadoB = vdadosdospark.substr(24, 1);

        if (resultadoB==1){
            document.write("<IMG ALIGN='center' "+
            "style='position:absolute; left: 400; top: 100' " +
            "SRC='http://www.uairobotics.com/tomada/Images/farol.png'> " +
            "<BR><BR>")
        }else
        {
            document.write("<IMG ALIGN='center' "+
            "style='position:absolute; left: 400; top: 100' " +
            "SRC='http://www.uairobotics.com/tomada/Images/f.png'> " +
            "<BR><BR>"); 
        }
    });
}, 5000);

Answer 1

使用.done()/.fail()方法 jQuery.getJSON()。

//first call
var flickerAPI = "http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?";
$.getJSON(flickerAPI, {
    tags: "mount rainier",
    tagmode: "any",
    format: "json"
  })
  .done(function(data) {
    $('#log').append('got data in first call<br>');
  })
  .fail(function(jqxhr, textStatus, error) {
    $('#log').append('got error in first call<br>');
  });

//second call
$.getJSON("willFail.js", {
    name: "John",
    time: "2pm"
  })
  .done(function(json) {
    $('#log').append('got data in second call<br>');
  })
  .fail(function(jqxhr, textStatus, error) {
    $('#log').append('got error in second call<br>');
  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p id="log"></p>

onerror 事件显示图片 - javascript

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