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我使用下面的代碼來建立一個基於API的表，並且當數組中的對象存在時很好（例如lineStatuses [0] .statusSeverityDescription） ，但是當有一個對象，在一個對象中，在一個數組中，它不起作用，我得到返回結果[object Object]。獲取JSON數組（API），其中對象是在與對象的對象使用Javascript
下面是從URL的JSON數據的樣本（我期待未定義的第一條記錄將被返回）：
[
{
"$type": "Tfl.Api.Presentation.Entities.Line, Tfl.Api.Presentation.Entities",
"id": "bakerloo",
"name": "Bakerloo",
"modeName": "tube",
"disruptions": [],
"created": "2016-06-03T12:36:54.19Z",
"modified": "2016-06-03T12:36:54.19Z",
"lineStatuses": [
{
"$type": "Tfl.Api.Presentation.Entities.LineStatus, Tfl.Api.Presentation.Entities",
"id": 0,
"statusSeverity": 10,
"statusSeverityDescription": "Good Service",
"created": "0001-01-01T00:00:00",
"validityPeriods": []
}
],
"routeSections": [],
"serviceTypes": [
{
"$type": "Tfl.Api.Presentation.Entities.LineServiceTypeInfo, Tfl.Api.Presentation.Entities",
"name": "Regular",
"uri": "/Line/Route?ids=Bakerloo&serviceTypes=Regular"
}
]
},
{
"$type": "Tfl.Api.Presentation.Entities.Line, Tfl.Api.Presentation.Entities",
"id": "central",
"name": "Central",
"modeName": "tube",
"disruptions": [],
"created": "2016-06-03T12:36:54.037Z",
"modified": "2016-06-03T12:36:54.037Z",
"lineStatuses": [
{
"$type": "Tfl.Api.Presentation.Entities.LineStatus, Tfl.Api.Presentation.Entities",
"id": 0,
"lineId": "central",
"statusSeverity": 5,
"statusSeverityDescription": "Part Closure",
"reason": "CENTRAL LINE: Saturday 11 and Sunday 12 June, no service between White City and Ealing Broadway/West Ruislip. This is to enable track replacement work at East Acton and Ruislip Gardens. Replacement buses operate.",
"created": "0001-01-01T00:00:00",
"validityPeriods": [
{
"$type": "Tfl.Api.Presentation.Entities.ValidityPeriod, Tfl.Api.Presentation.Entities",
"fromDate": "2016-06-11T03:30:00Z",
"toDate": "2016-06-13T01:29:00Z",
"isNow": false
}
],
"disruption": {
"$type": "Tfl.Api.Presentation.Entities.Disruption, Tfl.Api.Presentation.Entities",
"category": "PlannedWork",
"categoryDescription": "PlannedWork",
"description": "CENTRAL LINE: Saturday 11 and Sunday 12 June, no service between White City and Ealing Broadway/West Ruislip. This is to enable track replacement work at East Acton and Ruislip Gardens. Replacement buses operate.",
"additionalInfo": "Replacement buses operate as follows:Service A: White City - East Acton - North Acton - West Acton - Ealing Common (for District and Piccadilly Lines) - Ealing BroadwayService B: White City - North Acton - Northolt - South Ruislip - Ruislip Gardens - West RuislipService C: White City - North Acton - Park Royal (Piccadilly Line) - Hanger Lane - Perivale - Greenford - Northolt",
"created": "2016-05-12T11:04:00Z",
"affectedRoutes": [],
"affectedStops": [],
"isBlocking": true,
"closureText": "partClosure"
}
}
],
"routeSections": [],
"serviceTypes": [
{
"$type": "Tfl.Api.Presentation.Entities.LineServiceTypeInfo, Tfl.Api.Presentation.Entities",
"name": "Regular",
"uri": "/Line/Route?ids=Central&serviceTypes=Regular"
}
]
}
]
我也試圖用setInterval來刷新管破裂DIV與來自API的更新數據不一致。以下是代碼（URL返回上面的一些JSON數據）。任何想法我做錯了什麼？
var xmlhttp = new XMLHttpRequest();
var url = "https://api.tfl.gov.uk/line/mode/tube/status";
xmlhttp.onreadystatechange=function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
myFunctionDisruption(xmlhttp.responseText);
}
};
xmlhttp.open("GET", url, true);
xmlhttp.send();
setInterval(myFunctionDisruption, 600000);
function myFunctionDisruption(response) {
var arr = JSON.parse(response);
var i;
var out = "<table>";
for(i = 0; i < arr.length; i++) {
out += "<tr><td>" +
arr[i].lineStatuses[0].disruption.description + <!-- DOES NOT WORK -->
"</td></tr>";
}
out += "</table>";
document.getElementById("tube-disruption").innerHTML = out;
}