请帮助我从1小时开始尝试并且无法解决什么错误
<!DOCTYPE html>
<html>
<body>
<div id="id01">Result<br/></div>
<script>
var xmlhttp = new XMLHttpRequest();
var url = "http://it-ebooks-api.info/v1/book/2279690981";
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var myArr = JSON.parse(xmlhttp.responseText);
myFunction(myArr);
}
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
function myFunction(arr) {
var out = "";
var i;
for(i = 0; i < arr.length; i++) {
out = arr[i].ID + arr[i].Title + arr[i].Description;
}
document.getElementById("id01").innerHTML = out;
}
</script>
</body>
</html>
&#13;
我正在尝试从http://it-ebooks-api.info/v1/book/2279690981获取详细信息,但它只显示返回的空数组。需要进行哪些更改?
变形例 我在JSON对象上添加了[]并且它工作了..请有人解释一下。
提前感谢:)
答案 0 :(得分:0)
响应不包含数组,因此不需要for循环,这可以为您提供所需的结果:
<!DOCTYPE html>
<html>
<body>
<div id="id01">Result<br/></div>
<script>
var xmlhttp = new XMLHttpRequest();
var url = "http://it-ebooks-api.info/v1/book/2279690981";
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var myresponse = JSON.parse(xmlhttp.responseText);
myFunction(myresponse);
}
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
function myFunction(response) {
var out = "";
var i;
out = "<p>" + response.ID + response.Title + response.Description + "<p>";
document.getElementById("id01").innerHTML = out;
}
</script>
</body>
如果你使用http://it-ebooks-api.info/v1/search/php提供的完整列表,那么你需要for循环来完成这样的数组:
<!DOCTYPE html>
<html>
<body>
<div id="id01">Result<br/></div>
<script>
var xmlhttp = new XMLHttpRequest();
var url = "http://it-ebooks-api.info/v1/search/php";
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var myresponse = JSON.parse(xmlhttp.responseText);
myFunction(myresponse.Books);
}
}
function myFunction(Books) {
var out = "";
for (var i = 0; i < Books.length; i++) {
out += "<p>ID: " + Books[i].ID + "</p>" + "<p>Title: " + Books[i].Title + "</p>" + "<p>Description: " + Books[i].Description + "</p>"
}
document.getElementById("id01").innerHTML = out;
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
</script>
</body>
</html>
为了使它更优雅,你可以有一个添加书籍的功能,如果你只得到一本书,你可以直接从onreadystatechange调用它,如果你有完整的列表,那么你可以循环它,但仍然使用相同的功能。所以像这样:
<!DOCTYPE html>
<html>
<body>
<div id="id01">Result<br/></div>
<script>
var xmlhttp = new XMLHttpRequest();
var url = "http://it-ebooks-api.info/v1/search/php";
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var response = JSON.parse(xmlhttpo.responseText);
if (response.Books) { // If the response object has Books array, we pass it to the parseBooks functoin to add them all one by one.
parseBooks(response.Books)
} else {
addBook(response); // If there is no Books array, we assume that there is only one book and add it to the list with addBook function.
}
}
}
function addBook (Book) {
var text = document.getElementById("id01").innerHTML;
var body = "<p>ID: " + Book.ID + "</p><p>Title: " + Book.Title + "</p><p>Description: " + Book.Description + "</p>";
document.getElementById("id01").innerHTML = text + body; // Append the innerHTML with the new Book.
}
function parseBooks(Books) {
for (var i = 0; i < Books.length; i++) {
addBook(Books[i]) // Add all books in the array one by one
}
}
xmlhttp.open("GET", url, true);
xmlhttp.send();
</script>
</body>
</html>
答案 1 :(得分:0)
您的JSON Feed只是一个简单的对象,而不是一个对象数组。 请注意返回Feed中的大括号: {}
然后您应该更改myFunction
函数,使其仅通过删除for
循环来通过对象而不是数组:
function myFunction(obj) {
var out = "",
id01 = document.getElementById("id01");
out = obj.ID + obj.Title + obj.Description;
id01.innerHTML = id01.innerHTML + out;
}
当你必须解析一个对象数组时,你可以在for循环中使用相同的函数。
将 http://it-ebooks-api.info/v1/search/php 返回的JSON作为Feed,您可以检索Books
值,然后循环遍历它:
var xmlhttp = new XMLHttpRequest();
var url = "http://it-ebooks-api.info/v1/book/2279690981";
var url2 = "http://it-ebooks-api.info/v1/search/php";
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
var rslt = JSON.parse(xmlhttp.responseText);
console.log(rslt);
var books = rslt.Books;
for (var i = 0; i < books.length; i++)
{
myFunction(books[i]);
}
}
}
xmlhttp.open("GET", url2, true);
xmlhttp.send();