for (var i in colors) { typeof i; // string } for (var j = 0; j < colors.length; j++) { typoef i; // number } 至于为什么for..in在遍历数组时i为字符串?我的理解是如果我们从对象的视角来看待数组的话,实际上它是一个key为下标,value为数组元素值的对象,比如colors数组可以写成下面对象...
PropertyIsEnumerable(propertyName):用于检查给定的属性是否能够使用for-in语句来枚举。 toLocalString():返回对象的字符串表示,该字符串与执行环境的地区对应。 toString():返回对象的字符串表示。 valueOf():返回对象的字符串、数值或布尔值表示。 2.2.6 数据类型转换 字符串的颜色是黑色的,数值类型是蓝色的,布尔...
让我们使用in运算符来改进append(array,toAppend)函数: 代码语言:javascript 复制 functionappend(array,toAppend){constarrayCopy=array.slice();if('first'intoAppend){arrayCopy.unshift(toAppend.first);}if('last'intoAppend){arrayCopy.push(toAppend.last);}returnarrayCopy;}append([2,3,4],{first:1,la...
How to convert a string into integer in JavaScript - To convert a string into integer in JavaScript, is a simple task and can be converted using various approaches. Converting string to integer is useful for performing accurate mathematical operations, c
Boolean, Number, String 1.2 数组对象 : Array 1.3 工具对象:Math , Date 1.4 正则对象:RegExp 1.5 其他对象:Function ,Error,Global,Object 2.自定义对象 3.浏览器对象 4.ActiveX对象。 五、常用内置对象介绍: 1. Boolean,Number不建议直接使用。
container string | false false Appends the popover to a specific element container: 'body' Heads up! Options for individual popovers can alternatively be specified through the use of data attributes. 标记 For performance reasons, the Tooltip and Popover data-apis are opt in. If you would like...
localeCompare()Compares two strings in the current locale match()Searches a string for a value, or a regular expression, and returns the matches padEnd()Pads a string at the end padStart()Pads a string from the start prototypeAllows you to add properties and methods to an object ...
String 字符型:由一系列字符组成的字符串,属于值类型。 Number 数值型:用来表示数值,属于值类型,可以用于算术逻辑计算。 Boolean 布尔值型:用表示逻辑是,逻辑非:true,false,属于值类型。 Undefined 未定义:定义未赋值,或未定义(直接使用会引起异常),特殊的数据类原始数据型。
For data attributes, append the option name to data-, as in data-backdrop="". Nametypedefaultdescription backdrop boolean or the string 'static' true Includes a modal-backdrop element. Alternatively, specify static for a backdrop which doesn't close the modal on click. keyboard boolean true...
How to match and find the function calling from the string using regex in js? I have a string containing expressions such as calling to functions and properties: $ctrl.accounts$ctrl.fn() $ctrl.fns(arg) $ctrl.foo.bar$ctrl.bay.bag() $ctrl.bar.fn(arg)...