我有一份当前网络开发课程的作业，我的问题是我无法理解为什么需要使用JSON.parse()（这是一项要求）。我可以猜到它将被使用的地方，但实验并未设法呈现任何结果。
一般的想法是我们将JSON数组中的信息绘制在一个单独的文件中（显然在同一台服务器上）。这是通过讲师写的ajax.js文件中包含的函数完成的，该文件相对简单如下：
function getJSON(url, callbackFunction) {
//var request = new XMLHttpRequest();
var request = new XMLHttpRequest();
// Work around for browser caching problem that affects some browsers. It prevents
// the browser from using a cached copy that was stored by the browser from another visit.
if (url.indexOf('?') < 0) {
today = new Date();// Add a unique query string to the end of the url
// representing the current time to force the browser to fetch the data
// rather than using a locally cached copy that the browser fetched some earlier time.
url += '?' + today.getTime();
}
request.onreadystatechange = function (){
if (request.readyState === 4 && request.status===200) {
alert("Response Status = " + request.status); // You can safely comment out this line
alert("response = " + request.response); // You can safely comment out this line
alert("response headers = " + request.getAllResponseHeaders()); // You can safely comment out this line
callbackFunction(request.response);
}
};
try {
request.open("POST", url);
request.responseType ="json";
request.send();
}
catch ( exception ) {
alert(exception);
}
}
它使用XMLHTTPRequest函数。
这种情况下的回调函数目前如下：
function displayAllGames(results) {
alert('ready to start work');
var gamesArray = results.games;
var myHTML = '<table id="table1" border="1">';
for (var counter = 0; counter < gamesArray.length; counter++) {
var game = gamesArray[counter];
var venue = game.venue;
var round = game.round;
var date = new Date(game.date);
var homeTeam = game.homeTeam.name;
var awayTeam = game.awayTeam.name;
myHTML += '<tr>';
myHTML += '<td>' + round + '</td>';
myHTML += '<td>' + venue + '</td>';
myHTML += '<td>' + date.toLocaleDateString() + '</td>';
myHTML += '<td>' + homeTeam + '</td>';
myHTML += '<td>' + awayTeam + '</td>';
myHTML += '</tr>';
}
myHTML += '</table>';
var targetElement = document.getElementById('happyPlace');
targetElement.innerHTML = myHTML;
}
在为JSON.parse()添加代码时，即使作为文档末尾的额外内容，也没有任何反应。代码如下：
var parsedData = JSON.parse(gamesArray);
alert(parsedData[1]);
但是没有警报出现，甚至在尝试使用document.write将单个项目写入文档末尾时也没有出现任何警报。有人可以解释一下我做错了什么吗？这让我疯了。
JSON内容：
{
"games": [
{
"round": 1,
"date": "Fri, 3 Apr 2015 14:20:00",
"venue": "Maryborough",
"homeTeam":
{
"name": "Maryborough",
"goals": 11,
"points": 9
},
"awayTeam":
{
"name": "Castlemaine",
"goals": 24,
"points": 10
}
},
{
"round": 1,
"date": "Fri, 3 Apr 2015 14:20:00",
"venue": "Eaglehawk",
"homeTeam":
{
"name": "Eaglehawk",
"goals": 18,
"points": 19
},
"awayTeam":
{
"name": "South Bendigo",
"goals": 3,
"points": 7
}
},
{
"round": 1,
"date": "Fri, 3 Apr 2015 14:20:00",
"venue": "Gisborne",
"homeTeam":
{
"name": "Gisborne",
"goals": 10,
"points": 5
},
"awayTeam":
{
"name": "Kyneton",
"goals": 19,
"points": 11
}
},
{
"round": 1,
"date": "Fri, 3 Apr 2015 14:20:00",
"venue": "Golden Square",
"homeTeam":
{
"name": "Golden Square",
"goals": 16,
"points": 10
},
"awayTeam":
{
"name": "Kangaroo Flat",
"goals": 9,
"points": 10
}
},
{
"round": 1,
"date": "Fri, 3 Apr 2015 17:30:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "Sandhurst",
"goals": 10,
"points": 9
},
"awayTeam":
{
"name": "Strathfieldsaye",
"goals": 11,
"points": 16
}
},
{
"round": 2,
"date": "Sat, 11 Apr 2015 14:20:00",
"venue": "Gisborne",
"homeTeam":
{
"name": "Gisborne",
"goals": 25,
"points": 22
},
"awayTeam":
{
"name": "Maryborough",
"goals": 7,
"points": 3
}
},
{
"round": 2,
"date": "Sat, 11 Apr 2015 14:20:00",
"venue": "Kennington",
"homeTeam":
{
"name": "South Bendigo",
"goals": 10,
"points": 6
},
"awayTeam":
{
"name": "Golden Square",
"goals": 15,
"points": 18
}
},
{
"round": 2,
"date": "Sat, 11 Apr 2015 14:20:00",
"venue": "Kyneton",
"homeTeam":
{
"name": "Kyneton",
"goals": 15,
"points": 11
},
"awayTeam":
{
"name": "Sandhurst",
"goals": 22,
"points": 30
}
},
{
"round": 2,
"date": "Sat, 11 Apr 2015 17:30:00",
"venue": "Kangaroo Flat",
"homeTeam":
{
"name": "Kangaroo Flat",
"goals": 12,
"points": 12
},
"awayTeam":
{
"name": "Castlemaine",
"goals": 11,
"points": 10
}
},
{
"round": 2,
"date": "Sun, 12 Apr 2015 14:20:00",
"venue": "Strathfieldsaye",
"homeTeam":
{
"name": "Strathfieldsaye",
"goals": 16,
"points": 16
},
"awayTeam":
{
"name": "Eaglehawk",
"goals": 11,
"points": 7
}
},
{
"round": 3,
"date": "Sat, 18 Apr 2015 14:20:00",
"venue": "Maryborough",
"homeTeam":
{
"name": "Maryborough",
"goals": 12,
"points": 14
},
"awayTeam":
{
"name": "Kangaroo Flat",
"goals": 14,
"points": 13
}
},
{
"round": 3,
"date": "Sat, 18 Apr 2015 14:20:00",
"venue": "Castlemaine",
"homeTeam":
{
"name": "Castlemaine",
"goals": 12,
"points": 13
},
"awayTeam":
{
"name": "Gisborne",
"goals": 10,
"points": 10
}
},
{
"round": 3,
"date": "Sat, 18 Apr 2015 14:20:00",
"venue": "Eaglehawk",
"homeTeam":
{
"name": "Eaglehawk",
"goals": 20,
"points": 21
},
"awayTeam":
{
"name": "Kyneton",
"goals": 10,
"points": 8
}
},
{
"round": 3,
"date": "Sat, 18 Apr 2015 14:20:00",
"venue": "Golden Square",
"homeTeam":
{
"name": "Golden Square",
"goals": 6,
"points": 8
},
"awayTeam":
{
"name": "Strathfieldsaye",
"goals": 13,
"points": 13
}
},
{
"round": 3,
"date": "Sat, 18 Apr 2015 14:20:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "Sandhurst",
"goals": 20,
"points": 17
},
"awayTeam":
{
"name": "South Bendigo",
"goals": 8,
"points": 3
}
},
{
"round": 4,
"date": "Sat, 25 Apr 2015 14:20:00",
"venue": "Maryborough",
"homeTeam":
{
"name": "Maryborough",
"goals": 9,
"points": 4
},
"awayTeam":
{
"name": "Sandhurst",
"goals": 25,
"points": 26
}
},
{
"round": 4,
"date": "Sat, 25 Apr 2015 14:20:00",
"venue": "Eaglehawk",
"homeTeam":
{
"name": "Eaglehawk",
"goals": 26,
"points": 14
},
"awayTeam":
{
"name": "Kangaroo Flat",
"goals": 7,
"points": 3
}
},
{
"round": 4,
"date": "Sat, 25 Apr 2015 14:20:00",
"venue": "Strathfieldsaye",
"homeTeam":
{
"name": "Strathfieldsaye",
"goals": 10,
"points": 15
},
"awayTeam":
{
"name": "Castlemaine",
"goals": 3,
"points": 6
}
},
{
"round": 4,
"date": "Sat, 25 Apr 2015 14:20:00",
"venue": "Gisborne",
"homeTeam":
{
"name": "Gisborne",
"goals": 9,
"points": 13
},
"awayTeam":
{
"name": "Golden Square",
"goals": 11,
"points": 10
}
},
{
"round": 4,
"date": "Sat, 25 Apr 2015 17:30:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "South Bendigo",
"goals": 6,
"points": 11
},
"awayTeam":
{
"name": "Kyneton",
"goals": 10,
"points": 11
}
},
{
"round": 5,
"date": "Sat, 2 May 2015 14:20:00",
"venue": "Castlemaine",
"homeTeam":
{
"name": "Castlemaine",
"goals": 10,
"points": 8
},
"awayTeam":
{
"name": "Eaglehawk",
"goals": 9,
"points": 15
}
},
{
"round": 5,
"date": "Sat, 2 May 2015 14:20:00",
"venue": "Strathfieldsaye",
"homeTeam":
{
"name": "Strathfieldsaye",
"goals": 24,
"points": 24
},
"awayTeam":
{
"name": "Maryborough",
"goals": 5,
"points": 2
}
},
{
"round": 5,
"date": "Sat, 2 May 2015 14:20:00",
"venue": "Golden Square",
"homeTeam":
{
"name": "Golden Square",
"goals": 17,
"points": 10
},
"awayTeam":
{
"name": "Kyneton",
"goals": 7,
"points": 6
}
},
{
"round": 5,
"date": "Sat, 2 May 2015 14:20:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "South Bendigo",
"goals": 12,
"points": 19
},
"awayTeam":
{
"name": "Gisborne",
"goals": 4,
"points": 6
}
},
{
"round": 5,
"date": "Sat, 2 May 2015 17:30:00",
"venue": "Kangaroo Flat",
"homeTeam":
{
"name": "Kangaroo Flat",
"goals": 7,
"points": 8
},
"awayTeam":
{
"name": "Sandhurst",
"goals": 17,
"points": 24
}
},
{
"round": 6,
"date": "Sat, 9 May 2015 14:20:00",
"venue": "Maryborough",
"homeTeam":
{
"name": "Maryborough",
"goals": 6,
"points": 6
},
"awayTeam":
{
"name": "Golden Square",
"goals": 27,
"points": 26
}
},
{
"round": 6,
"date": "Sat, 9 May 2015 14:20:00",
"venue": "Kangaroo Flat",
"homeTeam":
{
"name": "Kangaroo Flat",
"goals": 11,
"points": 9
},
"awayTeam":
{
"name": "South Bendigo",
"goals": 8,
"points": 11
}
},
{
"round": 6,
"date": "Sat, 9 May 2015 14:20:00",
"venue": "Gisborne",
"homeTeam":
{
"name": "Gisborne",
"goals": 9,
"points": 4
},
"awayTeam":
{
"name": "Eaglehawk",
"goals": 19,
"points": 17
}
},
{
"round": 6,
"date": "Sat, 9 May 2015 14:20:00",
"venue": "Kyneton",
"homeTeam":
{
"name": "Kyneton",
"goals": 5,
"points": 8
},
"awayTeam":
{
"name": "Strathfieldsaye",
"goals": 20,
"points": 18
}
},
{
"round": 6,
"date": "Sun, 10 May 2015 14:20:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "Sandhurst",
"goals": 16,
"points": 17
},
"awayTeam":
{
"name": "Castlemaine",
"goals": 3,
"points": 7
}
},
{
"round": 7,
"date": "Sat, 16 May 2015 14:20:00",
"venue": "Kangaroo Flat",
"homeTeam":
{
"name": "Kangaroo Flat",
"goals": 9,
"points": 12
},
"awayTeam":
{
"name": "Strathfieldsaye",
"goals": 13,
"points": 11
}
},
{
"round": 7,
"date": "Sat, 16 May 2015 14:20:00",
"venue": "Castlemaine",
"homeTeam":
{
"name": "Castlemaine",
"goals": 18,
"points": 9
},
"awayTeam":
{
"name": "Kyneton",
"goals": 21,
"points": 13
}
},
{
"round": 7,
"date": "Sat, 16 May 2015 14:20:00",
"venue": "Eaglehawk",
"homeTeam":
{
"name": "Eaglehawk",
"goals": 8,
"points": 11
},
"awayTeam":
{
"name": "Golden Square",
"goals": 10,
"points": 14
}
},
{
"round": 7,
"date": "Sat, 16 May 2015 14:20:00",
"venue": "Gisborne",
"homeTeam":
{
"name": "Gisborne",
"goals": 1,
"points": 4
},
"awayTeam":
{
"name": "Sandhurst",
"goals": 17,
"points": 25
}
},
{
"round": 7,
"date": "Sat, 16 May 2015 14:20:00",
"venue": "Queen Elizabeth Oval",
"homeTeam":
{
"name": "South Bendigo",
"goals": 25,
"points": 18
},
"awayTeam":
{
"name": "Maryborough",
"goals": 5,
"points": 6
}
}
}
答案 0 :(得分：0)
根据我的理解，如果结果不是对象，则应使用JSON.parse，而使用包含有效JSON的字符串变量。这样你就可以使用Javacript对象并做任何你喜欢的事情。