freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/basic-javascript/find-the-length-of-a-string.md

id, challengeType, videoUrl, forumTopicId, title

id	challengeType	videoUrl	forumTopicId	title
bd7123c9c448eddfaeb5bdef	1	https://scrimba.com/c/cvmqEAd	18182	查找字符串的长度

Description

你可以通过在字符串变量或字符串后面写上.length来获得字符串变量值的长度。 "Alan Peter".length; // 10 例如，我们创建了一个变量var firstName = "Charles"，我们就可以通过使用firstName.length来获得"Charles"字符串的长度。

Instructions

使用.length属性来获得变量lastName的长度，并把它赋值给变量lastNameLength。

Tests

tests:
  - text: 不能改变 <code>// Setup</code> 部分声明的变量。
    testString: assert(code.match(/var lastNameLength = 0;/) && code.match(/var lastName = "Lovelace";/));   
  - text: <code>lastNameLength</code>应该等于 8。
    testString: assert(typeof lastNameLength !== 'undefined' && lastNameLength === 8); 
  - text: 你应该使用 <code>.length</code> 获取 <code>lastName</code> 的长度，像这样 <code>lastName.length</code>。
    testString: assert(code.match(/=\s*lastName\.length/g) && !code.match(/lastName\s*=\s*8/));

Challenge Seed

// Example
var firstNameLength = 0;
var firstName = "Ada";

firstNameLength = firstName.length;

// Setup
var lastNameLength = 0;
var lastName = "Lovelace";

// Only change code below this line.

lastNameLength = lastName;

Solution

var firstNameLength = 0;
var firstName = "Ada";
firstNameLength = firstName.length;

var lastNameLength = 0;
var lastName = "Lovelace";
lastNameLength = lastName.length;