This question already has an answer here: How do you check for an empty string in JavaScript? 39 answers function myFriday() { var input = document.getElementById("input1").value; var ever = function() { if (input.trim() == '') { return "Please input a number" } else if (!(isNaN(input))) { var result = 1; for (var i = 1; i <= input; i++) {
这个问题在这里已经有了答案： 你如何检查JavaScript中的空字符串？ 39个答案 function myFriday() { var input = document.getElementById("input1").value; var ever = function() { if (input.trim() == '') { return "Please input a number" } else if (!(isNaN(input))) { var result = 1; for (var i = 1; i <= input; i++) { result = result * i }
Possible Duplicate: What is the best way to check for an empty string in JavaScript? I know this is really basic, but I am new to javascript and can't find an answer anywhere. How can I check if a string is empty? 我检查长度。 if (str.length == 0) { } If you want to know if it's an empty string use === instead of ==. if(variable === "") { } This is because === will only return t
可能重复： 在JavaScript中检查空字符串的最佳方法是什么？ 我知道这是非常基本的，但我是JavaScript新手，无法在任何地方找到答案。 如何检查字符串是否为空？ 我检查长度。 if (str.length == 0) { } 如果你想知道它是一个空字符串，请使用===而不是==。 if(variable === "") { } 这是因为===只有在两边的值是相同类型的情况下才会返回true，在这种情况下是字符串。 例如：（false ==“”）将返回true，并且（false
Possible Duplicate: Removing whitespace from string in JavaScript I have used trim function to remove the white spaces at the beginning and end of the sentences. If there is to much white spaces in between words in a sentence, is there any method to trim? for example "abc def. fds sdff." var str = 'asdads adasd adsd'; str = str.replace(/s+/
可能重复： 在JavaScript中删除字符串中的空格 我已经使用修剪功能来删除句子开头和结尾处的空格。 如果句子中的单词之间有很多空白，是否有修剪的方法？ 例如 "abc def. fds sdff." var str = 'asdads adasd adsd'; str = str.replace(/s+/g, ' '); 我认为你正在寻找的是JavaScript的string.replace（）方法。 如果你想删除所有的空白，使用这个： "abc def. fds
Possible Duplicate: Remove non breaking space ( ) from between elements using jquery How to write a script to trim white space/tab between two element? For example, <tr> <td>A </td> <td>B </td> <td>C </td> </tr> Convert to, <tr><td>A </td><td>B </td><td
可能重复： 使用jQuery从元素之间移除非打破的空格（＆nbsp;） 如何编写脚本来修剪两个元素之间的空白/制表符？ 例如， <tr> <td>A </td> <td>B </td> <td>C </td> </tr> 转换成， <tr><td>A </td><td>B </td><td>C </td></tr> 例如，脚本应该删除第一个<td&
This question already has an answer here: Is floating point math broken? 23 answers The "solution" to the (non-)error is to ignore it, and ensure that you use an appropriate function, ie toFixed(n) , to present the number with the desired number of decimal places. It's important to know the difference between the internal representation of a value, and how to present that val
这个问题在这里已经有了答案： 浮点数学是否被破坏？ 23个答案 对（非）错误的“解决方案”是忽略它，并确保使用适当的函数，即toFixed(n)来显示具有所需小数位数的数字。 了解一个值的内部表示与如何将该值呈现给最终用户是很重要的。 您可以使用https://github.com/ekg/fraction.js库获取中间值，并将最终结果转换回十进制值以最大限度地减少错误。
So I have a Javascript script which adds small fractions together in a loop and its possible that it will add 0.2 to 0.1. Then that value is fed to another function but the issue is I need 0.3 to be fed exactly and not 0.30000000000000004. What is the simplest way to ensure the number is corrected and exact. Note that its possible to get 0.25+0.125 etc being added to simply rounding to 1 deci
所以我有一个Javascript脚本，它将循环中的小部分加在一起，并且它可能会增加0.2到0.1。 然后，这个值被馈送到另一个函数，但问题是我需要0.3，而不是0.30000000000000004。 确保数字得到更正和确切的最简单方法是什么？ 请注意，它可能得到0.25 + 0.125等被简单舍入到1小数不会解决问题。 也可以添加0.2 + 0.10000000000000004，虽然这是非常非常不可能的！ 通用浮点算法中避免舍入错误的方法并不简单。 数字0.3没有精
Possible Duplicate: Is JavaScript's Math broken? Why can't decimal numbers be represented exactly in binary? What will be result of next code: if(0.3 == ( 0.1 + 0.1 + 0.1 )) { alert(true); } else { alert(false); } It is strange, but result will be false. Reason is that result of 0.1+0.1+0.1 will be 0.30000000000000004 How can be explained this behavior? 解释
可能重复： JavaScript的数学是否被破坏？ 为什么十进制数不能完全用二进制表示？ 下一个代码的结果是什么： if(0.3 == ( 0.1 + 0.1 + 0.1 )) { alert(true); } else { alert(false); } 这很奇怪，但结果是错误的。 原因是这样的结果 0.1 + 0.1 + 0.1 将会 0.30000000000000004 如何解释这种行为？ 解释很简单 - 阅读浮点数问题 这也是1/3 + 1/3 + 1/3可能不会给你十进制数字1的原因。 如果你使
I have a class like so: import net from 'net'; import {EventEmitter} from 'events'; import Promise from 'bluebird'; class MyClass extends EventEmitter { constructor(host = 'localhost', port = 10011) { super(EventEmitter); this.host = host; this.port = port; this.socket = null; this.connect(); } connect() { this.socket = net.connect(thi
我有这样一个班级： import net from 'net'; import {EventEmitter} from 'events'; import Promise from 'bluebird'; class MyClass extends EventEmitter { constructor(host = 'localhost', port = 10011) { super(EventEmitter); this.host = host; this.port = port; this.socket = null; this.connect(); } connect() { this.socket = net.connect(this.por
I want to set the CSS counter-increment attribute on " .demo:before " using jQuery. The problem is jQuery cannot access a pseudo element. Another SO answer (which I can't seem to find now) suggested setting a data-attribute, and then using that value within the CSS, but that isn't working either. Is this something that can be accomplished? Simplified Example: http://jsfidd
我想使用jQuery在“ .demo:before ”上设置CSS counter-increment属性。 问题是jQuery无法访问伪元素。 另一个SO答案（我现在似乎找不到）建议设置一个数据属性，然后在CSS中使用该值，但这也不起作用。 这是可以实现的吗？ 简化示例：http://jsfiddle.net/4h7hk8td/ HTML： <ul class="demo"> <li></li> <li></li> <li></li> <li></li> <l
I'm trying to create a small project with video sprites, modeled after this JSFiddle for audio sprites. Playback works as expected: clicking on the relevant buttons play the relevant portions of the video. Now, however, I would like to incorporate something that would make the video play in full screen (or full window) when the button is pressed or when a key is pressed. The demo here, f
我正在尝试创建一个带有视频小精灵的小项目，模仿这个JSFiddle后面的音频小精灵。 播放按预期工作：单击相关按钮播放视频的相关部分。 但是，现在我想要加入一些东西，当按下按钮或按下某个按键时，可以使视频在全屏（或全窗口）中播放。 例如，此处的演示展示了一种方法，如果您在播放视频时单击Enter，它将进入全屏模式。 我对JavaScript并没有特别的经验，所以解决方案很可能面临着如何整合Mozilla文章中显示的方法，