49 lines
1.4 KiB
Markdown
49 lines
1.4 KiB
Markdown
---
|
||
title: String Length
|
||
localeTitle: 字符串长度
|
||
---
|
||
`length`属性表示字符串的长度。
|
||
|
||
## 句法
|
||
```
|
||
str.length
|
||
```
|
||
|
||
[MDN链接](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length) | [MSDN链接](https://msdn.microsoft.com/en-us/LIBRary/3d616214%28v=vs.94%29.aspx)
|
||
|
||
## 描述
|
||
|
||
此属性返回字符串中的代码单元数。 UTF-16是JavaScript使用的字符串格式，使用单个16位代码单元来表示最常见的字符，但需要使用两个代码单元来表示不常用的字符，因此有可能将长度返回的值返回到不匹配字符串中的实际字符数。
|
||
|
||
对于空字符串，长度为0。
|
||
|
||
静态属性`String.length`返回值1。
|
||
|
||
## 例子
|
||
```
|
||
var x = 'Mozilla';
|
||
var empty = '';
|
||
|
||
console.log('Mozilla is ' + x.length + ' code units long');
|
||
/* "Mozilla is 7 code units long" */
|
||
|
||
console.log('The empty string has a length of ' + empty.length);
|
||
/* "The empty string has a length of 0" */
|
||
|
||
var str = "every good boy does fine";
|
||
var start = 0;
|
||
var end = str.length - 1;
|
||
var tmp = "";
|
||
var arr = new Array(end);
|
||
|
||
while (end >= 0) {
|
||
arr[start++] = str.charAt(end--);
|
||
}
|
||
|
||
// Join the elements of the array with a
|
||
var str2 = arr.join('');
|
||
document.write(str2);
|
||
|
||
// Output: enif seod yob doog yreve
|
||
|
||
``` |