Error: Cannot read property 'text' of undefined

Question

我在运行这个时候标题有误。我试图在没有任何 html 而运行 this

的情况下解析第一段

HTML

<div id="headingWiki_0"><h3><span>Roman empire</span></h3></div>

JS

var titolo = $("#headingWiki_0 h3 span").text();
  $.getJSON("https://it.wikipedia.org/w/api.php?action=parse&format=json&prop=text&callback=?", {
    page: titolo
  }, function(data) {
    var markupt = data.parse.text["*"];
    var blurbt = $('<div></div>').html(markup);
    blurbt.find(".mw-editsection, #toc, .noprint, .thumb, img, table").remove();
    // remove links as they will not work
    blurbt.find('a').each(function() { $(this).replaceWith($(this).html()); });
    // remove any references
    blurbt.find('sup').remove();
    // remove cite error
    blurbt.find('.mw-ext-cite-error').remove();
    $('#usp-custom-4').val($(blurbt).find('p'));

  });

控制台说：

Uncaught TypeError: Cannot read property 'text' of undefined

Answer 1

只需从 url 中删除 &callback=?。它应该看起来像：

https://it.wikipedia.org/w/api.php?action=parse&format=json&prop=text&page=titolo

您使用的 url 没有 return 一个 JSON，但是这个应该可以。

如果您有 CORS 问题，那么您应该提出 JSONP 个请求：

function onSuccess(data){
    var markupt = data.parse.text["*"];
    var blurbt = $('<div></div>').html(markup);
    blurbt.find(".mw-editsection, #toc, .noprint, .thumb, img, table").remove();
    // remove links as they will not work
    blurbt.find('a').each(function() { $(this).replaceWith($(this).html()); });
    // remove any references
    blurbt.find('sup').remove();
    // remove cite error
    blurbt.find('.mw-ext-cite-error').remove();
    $('#usp-custom-4').val($(blurbt).find('p'));
}

$.ajax({
    url: "https://it.wikipedia.org/w/api.php?action=parse&format=json&prop=text&page=titolo",
    dataType: "jsonp",
    jsonpCallback: "onSuccess"
})

Answer 2

多亏了我从另一个那里得到的，这是有效的代码

$("#wiki").on("click", function(){
 firstWiki();
});


function onSuccess(data){
      var markupt = data.parse.text["*"];
      $('#usp-custom-4').text(markupt);
      console.log(markupt);
      var blurbt = $('<div></div>').html(markupt);
      blurbt.find(".mw-editsection, #toc, .noprint, .thumb, img, table").remove();
      // remove links as they will not work
      blurbt.find('a').each(function() { $(this).replaceWith($(this).html()); });
      // remove any references
      blurbt.find('sup').remove();
      // remove cite error
      blurbt.find('.mw-ext-cite-error').remove();
      var pOnly  = $(blurbt).find('p').text();
}

function firstWiki() {
  var titolo = $("#headingWiki_0 h3 span").text();
  titolo = encodeURIComponent(titolo);
  $.ajax({
    url: "https://it.wikipedia.org/w/api.php?action=parse&format=json&prop=text&section=0&page=" + titolo + "&callback=?",
    contentType: "application/json; charset=utf-8",
    dataType: "jsonp",
    success: onSuccess
  });
}

textarea {
  width: 100%;
  height: 200px;
}

input[type=checkbox] {
  display: none;
}

input[type=checkbox] + label {
  background: #999;
  display: inline-block;
  padding: 0;
}

input[type=checkbox]:checked + label {
  border: 10px solid grey;
  padding: 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="headingWiki_0"><h3><span>Impero romano</span></h3></div>
<button id="wiki">
Load
</button>
<textarea id="usp-custom-4"></textarea>

$("#wiki").on("click", function(){
 firstWiki();
});


function onSuccess(data){
      var markupt = data.parse.text["*"];
      console.log(markupt);
      var blurbt = $('<div></div>').html(markupt);
      blurbt.find(".mw-editsection, #toc, .noprint, .thumb, img, table").remove();
      // remove links as they will not work
      blurbt.find('a').each(function() { $(this).replaceWith($(this).html()); });
      // remove any references
      blurbt.find('sup').remove();
      // remove cite error
      blurbt.find('.mw-ext-cite-error').remove();
      var pOnly  = $(blurbt).find('p').text();
      $('#usp-custom-4').text(pOnly);
}

function firstWiki() {
  var titolo = $("#headingWiki_0 h3 span").text();
  titolo = encodeURIComponent(titolo);
  $.ajax({
    url: "https://it.wikipedia.org/w/api.php?action=parse&format=json&prop=text&section=0&page=" + titolo + "&callback=?",
    contentType: "application/json; charset=utf-8",
    dataType: "jsonp",
    success: onSuccess
  });
}

textarea {
  width: 100%;
  height: 200px;
}

input[type=checkbox] {
  display: none;
}

input[type=checkbox] + label {
  background: #999;
  display: inline-block;
  padding: 0;
}

input[type=checkbox]:checked + label {
  border: 10px solid grey;
  padding: 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="headingWiki_0"><h3><span>Impero romano</span></h3></div>
<button id="wiki">
Load
</button>
<textarea id="usp-custom-4"></textarea>

Error: Cannot read property 'text' of undefined

Error: Cannot read property 'text' of undefined

javascript

jquery

wikipedia

wikipedia-api