我试图将嵌套的JSON数据转换为HTML表，但它一直在抛出错误。
我不确定我做错了什么。在对象内部访问数组的方法可能有些问题？
它不断抛出这个错误：
＆＃34;无法设置属性＆inner;内部HTML＆＃39; of null＆＃34;
以下是我写的代码：
function DonutTable(array){
//create a table element
var table = document.createElement("table");
//create header columns
var col = Object.keys(array[0]); //array of keys
//write keys onto the header cell
var tr = table.insertRow(-1);
col.forEach(function(key){
var th = document.createElement("th");
th.textContent = key;
tr.appendChild(th);
});
//create rows to hold the rest of the data
array.forEach(function(obj){
//for each obj in the main array, create a row
var data_row = table.insertRow(-1);
//for each header in the col array, populate data
col.forEach(function(key){
var tabCell = data_row.insertCell(-1);
if (key==="batters"){
//grab the value of batters and access value of batter
obj["batters"]["batter"].forEach(function(e){
//for each e in batter, create a div element
var div = document.createElement("div");
//write on the div
div.textContent = e.type + "(" + e.id + ")";
tabCell.appendChild(div); })
}
if (Array.isArray(obj[key])){ //check if a value of a key is an array
obj[key].forEach(function(topping){
//for each obj in topping, get id and type
var div = document.createElement("div");
div.textContent = topping.type + "(" + topping.id + ")";
tabCell.appendChild(div);
})
}
else{
tabCell.textContent = obj[key];
}
})
})
var divContainer = document.getElementById("showTable");
divContainer.innerHTML = "";
divContainer.appendChild(table);
}
var donut = [
{
"id": "0001",
"type": "donut",
"name": "Cake",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" },
{ "id": "1002", "type": "Chocolate" },
{ "id": "1003", "type": "Blueberry" },
{ "id": "1004", "type": "Devil's Food" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5005", "type": "Sugar" },
{ "id": "5007", "type": "Powdered Sugar" },
{ "id": "5006", "type": "Chocolate with Sprinkles" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
},
{
"id": "0002",
"type": "donut",
"name": "Raised",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5005", "type": "Sugar" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
},
{
"id": "0003",
"type": "donut",
"name": "Old Fashioned",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" },
{ "id": "1002", "type": "Chocolate" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
}
]
DonutTable(donut);
<html>
<head>
<title>HTML Donut Table from JSON</title>
<script type="text/javascript" src="script.js"></script>
</head>
<body>
<input type="button" value="Generate a table" onclick="DonutTable()">
<div id="showTable"></div>
</body>
</html>
答案 0 :(得分：2)
在Chrome中，在声明divContainer后立即设置断点。根据代码，看起来divContainer为null，因为您在页面上的HTML之前运行JavaScript。将JS移动到document.ready类型函数或将脚本部分移动到HTML下面。
答案 1 :(得分：2)
这是我刚才分成JS和HTML部分的确切代码。
它适用于初始运行，因为donut数组已显式传递给DonutTable()函数。由于您的HTML在没有参数的情况下调用DonutTable()，因此无法在按钮点击时使用。
function DonutTable(array){
//create a table element
var table = document.createElement("table");
//create header columns
var col = Object.keys(array[0]); //array of keys
//write keys onto the header cell
var tr = table.insertRow(-1);
col.forEach(function(key){
var th = document.createElement("th");
th.textContent = key;
tr.appendChild(th);
});
//create rows to hold the rest of the data
array.forEach(function(obj){
//for each obj in the main array, create a row
var data_row = table.insertRow(-1);
//for each header in the col array, populate data
col.forEach(function(key){
var tabCell = data_row.insertCell(-1);
if (key==="batters"){
//grab the value of batters and access value of batter
obj["batters"]["batter"].forEach(function(e){
//for each e in batter, create a div element
var div = document.createElement("div");
//write on the div
div.textContent = e["type"] + "(" + e["id"] + ")";
tabCell.appendChild(div); })
}
else if (Array.isArray(obj[key])){ //check if a value of a key is an array
obj[key].forEach(function(topping){
//for each obj in topping, get id and type
var div = document.createElement("div");
div.textContent = topping.type + "(" + topping.id + ")";
tabCell.appendChild(div);
})
}
else{
tabCell.textContent = obj[key];
}
})
})
var divContainer = document.getElementById("showTable");
divContainer.innerHTML = "";
divContainer.appendChild(table);
}
var donut = [
{
"id": "0001",
"type": "donut",
"name": "Cake",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" },
{ "id": "1002", "type": "Chocolate" },
{ "id": "1003", "type": "Blueberry" },
{ "id": "1004", "type": "Devil's Food" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5005", "type": "Sugar" },
{ "id": "5007", "type": "Powdered Sugar" },
{ "id": "5006", "type": "Chocolate with Sprinkles" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
},
{
"id": "0002",
"type": "donut",
"name": "Raised",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5005", "type": "Sugar" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
},
{
"id": "0003",
"type": "donut",
"name": "Old Fashioned",
"ppu": 0.55,
"batters":
{
"batter":
[
{ "id": "1001", "type": "Regular" },
{ "id": "1002", "type": "Chocolate" }
]
},
"topping":
[
{ "id": "5001", "type": "None" },
{ "id": "5002", "type": "Glazed" },
{ "id": "5003", "type": "Chocolate" },
{ "id": "5004", "type": "Maple" }
]
}
]
DonutTable(donut);<html>
<head>
<title>HTML Donut Table from JSON</title>
<script type="text/javascript" src="script.js"></script>
</head>
<body>
<input type="button" value="Generate a table" onclick="DonutTable()">
<div id="showTable"></div>
</body>
</html>