Are trailing commas standard in JavaScript, or do most browsers like Chrome and Firefox just tolerate them? I thought they were standard, but IE8 puked after encountering one—of course IE not supporting something hardly means it's not standard. Here's an example of what I mean (after the last element of the books array): var viewModel = { books: ko.observableArray([ { tit
在JavaScript中尾随逗号是标准的，还是像Chrome和Firefox这样的大多数浏览器只是容忍它们？ 我认为它们是标准的，但IE8在遇到IE之后呕吐，当然IE不支持某些事情几乎意味着它不是标准。 下面是我的意思（在books数组的最后一个元素之后）的例子： var viewModel = { books: ko.observableArray([ { title: "..", display: function() { return ".."; } }, { title: "..", display: function() { return "
This question already has an answer here: Length of a JavaScript object 32 answers You can do this: Object.getOwnPropertyNames(treeObj).length; // 3 getOwnPropertyNames returns array of properties of treeObj whose length can be checked. To count the number of properties an object has, you need to loop through the properties but remember to use the hasOwnProperty function: var count = 0;
这个问题在这里已经有了答案： JavaScript对象32的长度应答 你可以这样做： Object.getOwnPropertyNames(treeObj).length; // 3 getOwnPropertyNames返回可检查length的treeObj的属性数组。 要计算对象具有的属性数量，您需要遍历属性，但请记住使用hasOwnProperty函数： var count = 0; for (var p in obj) { if (obj.hasOwnProperty(p)) { count++; } } 如果你忘记这么做，你将循环访问继承的属性
This question already has an answer here: Length of a JavaScript object 32 answers Arrays have a length property. Objects do not (by default). I think the problem is on the php end ... You should be encoding an array and sending that back instead. Arrays are zero-indexed, so that may be the problem. Perhaps json_encode(array_values($msg)) . If your keys are correct after all, give Objec
这个问题在这里已经有了答案： JavaScript对象32的长度应答 数组有length属性。 对象不（默认）。 我认为这个问题是在PHP端...你应该编码一个数组并将其发回。 数组是零索引的，所以这可能是问题。 也许json_encode(array_values($msg)) 。 如果你的密钥是正确的，给Object.keys(msg).length一个镜头。 这可以是JavaScript对象的长度的重复 看看接受的答案。 顺便说一句，刚刚发现谷歌搜索“JavaScript对象的长度
This question already has an answer here: Length of a JavaScript object 32 answers .length属性仅适用于数字索引的属性。
这个问题在这里已经有了答案： JavaScript对象32的长度应答 .length属性仅适用于数字索引的属性。
This question already has an answer here: Length of a JavaScript object 32 answers You could use Object.keys() to obtain an array of keys, then count them: Object.keys(array).length Or, if you're targeting ECMAScript 3 or otherwise don't have Object.keys() , then you can count the keys manually: var length = 0; for (var key in array) { if (array.hasOwnProperty(key)) { +
这个问题在这里已经有了答案： JavaScript对象32的长度应答 你可以使用Object.keys()来获得一组键，然后对它们进行计数： Object.keys(array).length 或者，如果您的目标是ECMAScript 3或者没有Object.keys() ，那么您可以手动计算密钥： var length = 0; for (var key in array) { if (array.hasOwnProperty(key)) { ++length; } } 尽管这种方法存在一些边缘情况，但取决于您的目标浏览器，因此使用Moz
This question already has an answer here: Length of a JavaScript object 32 answers Object.keys(Accounts).length You are trying to get the "length" of an object, which does not exist. If this were an array, it would be enclosed in a bracket []. This is definitely an object, so in order to count the properties inside an object, you would have to use Object.keys() to contain the pro
这个问题在这里已经有了答案： JavaScript对象32的长度应答 Object.keys(Accounts).length 您正试图获取不存在的对象的“长度”。 如果这是一个数组，它将被括在括号[]中。 这绝对是一个对象，因此为了统计对象内的属性，必须使用Object.keys（）来包含数组中的属性名称，然后对其中的元素进行计数。 您可以使用for循环遍历对象中的所有元素和计数以获取数字： var Accounts = { 'Account001' : { 'data1' : 'foo1', 'data
Possible Duplicate: Length of a JavaScript object (that is, associative array) I have JSON in the following format [{"student":{"name" : "ABCD", "age":8, } "user":{ "firstName":"ABCD", "age": 9, } }, {"student":{"name" : "XCYS", "age":10, } "user":{ "firstName":"GGG", "age": 11, } },] I tried using (dat
可能的重复： JavaScript对象的长度（即关联数组） 我有以下格式的JSON [{"student":{"name" : "ABCD", "age":8, } "user":{ "firstName":"ABCD", "age": 9, } }, {"student":{"name" : "XCYS", "age":10, } "user":{ "firstName":"GGG", "age": 11, } },] 我尝试使用(data.student[i].length) ，这不起作用（只是看看对象的长
This question already has an answer here: Length of a JavaScript object 32 answers 遍历数组并获取对象属性名称。 var legend = [{ "min": 0, "max": 'first_color', "color": "#1a9850" }, { "min": 'first_color', "max": 'sec_color', "color": "#fee08b" }, { "min": 'sec_color', "max": 'thrd_color', "color": "#ff3300" }, { "min": 'thrd_color', "max": 'frth_color',
这个问题在这里已经有了答案： JavaScript对象32的长度应答 遍历数组并获取对象属性名称。 var legend = [{ "min": 0, "max": 'first_color', "color": "#1a9850" }, { "min": 'first_color', "max": 'sec_color', "color": "#fee08b" }, { "min": 'sec_color', "max": 'thrd_color', "color": "#ff3300" }, { "min": 'thrd_color', "max": 'frth_color', "color": "#d73027", "Abc
This question already has an answer here: Length of a JavaScript object 32 answers That because coordinates is Object not Array , use for..in var coordinates = { "a": [ [1, 2], [8, 9], [3, 5], [6, 1] ], "b": [ [5, 8], [2, 4], [6, 8], [1, 9] ] }; for (var i in coordinates) { console.log(coordinate
这个问题在这里已经有了答案： JavaScript对象32的长度应答 因为coordinates是Object not Array ，所以用于for..in var coordinates = { "a": [ [1, 2], [8, 9], [3, 5], [6, 1] ], "b": [ [5, 8], [2, 4], [6, 8], [1, 9] ] }; for (var i in coordinates) { console.log(coordinates[i]) } 或Object.keys var coord
Possible Duplicate: Length of Javascript Associative Array I want to check the length of a multidimensional array but I get "undefined" as the return. I'm assuming that I am doing something wrong with my code but I can't see anything odd about it. alert(patientsData.length); //undefined alert(patientsData["XXXXX"].length); //undefined alert(patientsData["XXXXX"]['firstName
可能重复： Javascript关联数组的长度 我想检查一个多维数组的长度，但我得到“未定义”作为返回。 我假设我的代码有问题，但我看不出有什么奇怪的地方。 alert(patientsData.length); //undefined alert(patientsData["XXXXX"].length); //undefined alert(patientsData["XXXXX"]['firstName']); //a name fruits = ["Banana", "Orange", "Apple", "Mango"]; alert(fruits.length); //4 思考？ 这可能与范围有关吗？ 该