11)for in Array 例3.11.1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> var a=['hello','teacher','马克-to-win']; for(var iii in a){ this.document.write('inidex'+iii+'的值是'+a[iii]+""); } ...
11)for in Array 例 3.11.1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
for...in 循环只会迭代可枚举的非符号属性。从内置构造函数(如 Array 和Object)创建的对象会从 Array.prototype 和Object.prototype 继承不可枚举属性,例如 Array 的indexOf() 方法或 Object 的toString() 方法,它们在 for...in 循环中不会被访问到。 根据现代 ECMAScript 规范的定义,遍历的顺序是一致且可预测...
4.6 Use Array.from instead of spread ... for mapping over iterables, because it avoids creating an intermediate array. // bad const baz = [...foo].map(bar); // good const baz = Array.from(foo, bar);4.7 Use return statements in array method callbacks. It’s ok to omit the ...
join()Joins all elements of an array into a string keys()Returns a Array Iteration Object, containing the keys of the original array lastIndexOf()Search the array for an element, starting at the end, and returns its position lengthSets or returns the number of elements in an array ...
1、从测试结果上看 stackoverflow 上也有这个讨论，For-loop performance: storing array length in a ...
JavaScript String match() Thematch()method returns an array containing the results of matching a string against a string (or a regular expression). Examples Perform a search for "ain": lettext ="The rain in SPAIN stays mainly in the plain"; ...
JavaScript offers several ways to check if an array includes a specific value. In this article, we will explore some of the most common methods for checking for the presence of a value in an array. The first method we will look at is the indexOf() method. This method returns the index...
Templating engines allow you to perform string interpolation.mustache.js - Minimal templating with {{mustaches}} in JavaScript. handlebars.js - An extension to the Mustache templating language. nunjucks - A rich and powerful templating language for JavaScript from Mozilla. hogan.js - A compiler for...