nodelist

问题 When looking at the ECMAScript compatibility table, it says that Edge 15 and Edge 16 support for ... of loops. However, when I run this code: const list = document.querySelectorAll('[data-test]'); console.log(list); for (const item of list) { console.log(item); } <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> It works in Chrome and Firefox, but not in Edge. Instead it says: Object doesn't support property or method 'Symbol

问题 When looking at the ECMAScript compatibility table, it says that Edge 15 and Edge 16 support for ... of loops. However, when I run this code: const list = document.querySelectorAll('[data-test]'); console.log(list); for (const item of list) { console.log(item); } <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> It works in Chrome and Firefox, but not in Edge. Instead it says: Object doesn't support property or method 'Symbol

问题 When looking at the ECMAScript compatibility table, it says that Edge 15 and Edge 16 support for ... of loops. However, when I run this code: const list = document.querySelectorAll('[data-test]'); console.log(list); for (const item of list) { console.log(item); } <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> It works in Chrome and Firefox, but not in Edge. Instead it says: Object doesn't support property or method 'Symbol

问题 When looking at the ECMAScript compatibility table, it says that Edge 15 and Edge 16 support for ... of loops. However, when I run this code: const list = document.querySelectorAll('[data-test]'); console.log(list); for (const item of list) { console.log(item); } <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> <div data-test></div> It works in Chrome and Firefox, but not in Edge. Instead it says: Object doesn't support property or method 'Symbol

问题 I am using a forEach to loop through a nodeList. My code is as follows var array = document.querySelectorAll('items'); array.forEach(function (item) { console.log(item); }); And this code throws an error as Uncaught TypeError: array.forEach is not a function Then after reading few online blog articles i changed the code to this. [].forEach.call(array, (function (item) { console.log(item); })); Could someone please explain why it is not possible to call forEach on a nodeList and what does the

问题 I am using a forEach to loop through a nodeList. My code is as follows var array = document.querySelectorAll('items'); array.forEach(function (item) { console.log(item); }); And this code throws an error as Uncaught TypeError: array.forEach is not a function Then after reading few online blog articles i changed the code to this. [].forEach.call(array, (function (item) { console.log(item); })); Could someone please explain why it is not possible to call forEach on a nodeList and what does the

问题 Lots of JavaScript libraries (jQuery, Zepto) seem to be calling Array.prototype.slice.call on querySelectorAll(), getElementsByTag or ClassName results... From reading many many similar questions/answers on StackOverflow I do understand that its to convert a NodeList result to a real Array so that you can invoke Array methods (slice, pop) on the results which are not available on NodeLists - but what I don't understand is why? You don't usually really need slice/pop on a list of DOM nodes +

问题 So I have a xml doc that I've declared here: DocumentBuilder dBuilder = dbFactory_.newDocumentBuilder(); StringReader reader = new StringReader(s); InputSource inputSource = new InputSource(reader); doc_ = dBuilder.parse(inputSource); Then I have a function where I pass in a string and I want to match that to an element in my xml: void foo(String str) { NodeList nodelist = doc_.getDocumentElement().getElementsByTagName(str); } The problem is when the str comes in it doesn't have any sort of

问题 The DOM NodeList (as returned e.g. by element.getElementsByTagName) is an interesting object, in that it is not a snapshot, but reflects changes to the document made after you have created the NodeList. I was wondering how one would implement such a collection: Completely lazy evaluation must be horribly slow, but keeping a cached version consistent requires a lot of book-keeping internally. I tried to google for blog articles on the subject, and also tried to find the relevant source code

问题 The DOM NodeList (as returned e.g. by element.getElementsByTagName) is an interesting object, in that it is not a snapshot, but reflects changes to the document made after you have created the NodeList. I was wondering how one would implement such a collection: Completely lazy evaluation must be horribly slow, but keeping a cached version consistent requires a lot of book-keeping internally. I tried to google for blog articles on the subject, and also tried to find the relevant source code