String

String object is used to represent and manipulate a sequence of characters.

描述

Strings are useful for holding data that can be represented in text form. Some of the most-used operations on strings are to check their length , to build and concatenate them using the + and += string operators , checking for the existence or location of substrings with the indexOf() method, or extracting substrings with the substring() 方法。

Creating strings

Strings can be created as primitives, from string literals, or as objects, using the String() constructor:

const string1 = "A string primitive";
const string2 = 'Also a string primitive';
const string3 = `Yet another string primitive`;
					
const string4 = new String("A String object");
					

String primitives and string objects can be used interchangeably in most situations. See " String primitives and String objects " below.

String literals can be specified using single or double quotes, which are treated identically, or using the backtick character ` . This last form specifies a template literal : with this form you can interpolate expressions.

Character access

There are two ways to access an individual character in a string. The first is the charAt() method:

return 'cat'.charAt(1) // returns "a"
					

The other way (introduced in ECMAScript 5) is to treat the string as an array-like object, where individual characters correspond to a numerical index:

return 'cat'[1] // returns "a"
					

When using bracket notation for character access, attempting to delete or assign a value to these properties will not succeed. The properties involved are neither writable nor configurable. (See Object.defineProperty() for more information.)

Comparing strings

In C, the strcmp() function is used for comparing strings. In JavaScript, you just use the less-than and greater-than operators :

let a = 'a'
let b = 'b'
if (a < b) { // true
  console.log(a + ' is less than ' + b)
} else if (a > b) {
  console.log(a + ' is greater than ' + b)
} else {
  console.log(a + ' and ' + b + ' are equal.')
}
					

A similar result can be achieved using the localeCompare() method inherited by String 实例。

注意: a == b compares the strings in a and b for being equal in the usual case-sensitive way. If you wish to compare without regard to upper or lower case characters, use a function similar to this:

function isEqual(str1, str2)
{
    return str1.toUpperCase() === str2.toUpperCase()
} // isEqual
					

Upper case is used instead of lower case in this function, due to problems with certain UTF-8 character conversions.

String primitives and String objects

Note that JavaScript distinguishes between String objects and primitive string values. (The same is true of Boolean and 数字 .)

String literals (denoted by double or single quotes) and strings returned from String calls in a non-constructor context (that is, called without using the new keyword) are primitive strings. JavaScript automatically converts primitives to String objects, so that it's possible to use String object methods for primitive strings. In contexts where a method is to be invoked on a primitive string or a property lookup occurs, JavaScript will automatically wrap the string primitive and call the method or perform the property lookup.

let s_prim = 'foo'
let s_obj = new String(s_prim)
console.log(typeof s_prim) // Logs "string"
console.log(typeof s_obj)  // Logs "object"
					

String primitives and String objects also give different results when using eval() . Primitives passed to eval are treated as source code; String objects are treated as all other objects are, by returning the object. For example:

let s1 = '2 + 2'              // creates a string primitive
let s2 = new String('2 + 2')  // creates a String object
console.log(eval(s1))         // returns the number 4
console.log(eval(s2))         // returns the string "2 + 2"
					

For these reasons, the code may break when it encounters String objects when it expects a primitive string instead, although generally, authors need not worry about the distinction.

A String object can always be converted to its primitive counterpart with the valueOf() 方法。

console.log(eval(s2.valueOf()))  // returns the number 4
					

Escape notation

Special characters can be encoded using escape notation:

Code Output
\ XXX
(where XXX is 1–3 octal digits; range of 0 377 )
ISO-8859-1 character / Unicode code point between U+0000 and U+00FF
\' single quote
\" double quote
\\ backslash
\n new line
\r carriage return
\v vertical tab
\t tab
\b backspace
\f form feed
\u XXXX (where XXXX is 4 hex digits; range of 0x0000 0xFFFF ) UTF-16 code unit / Unicode code point between U+0000 and U+FFFF
\u{ X } ... \u{ XXXXXX }
(where X XXXXXX is 1–6 hex digits; range of 0x0 0x10FFFF )
UTF-32 code unit / Unicode code point between U+0000 and U+10FFFF
\x XX
(where XX is 2 hex digits; range of 0x00 0xFF )
ISO-8859-1 character / Unicode code point between U+0000 and U+00FF

Long literal strings

Sometimes, your code will include strings which are very long. Rather than having lines that go on endlessly, or wrap at the whim of your editor, you may wish to specifically break the string into multiple lines in the source code without affecting the actual string contents. There are two ways you can do this.

Method 1

可以使用 + operator to append multiple strings together, like this:

let longString = "This is a very long string which needs " +
                 "to wrap across multiple lines because " +
                 "otherwise my code is unreadable."
					

Method 2

You can use the backslash character ( \ ) at the end of each line to indicate that the string will continue on the next line. Make sure there is no space or any other character after the backslash (except for a line break), or as an indent; otherwise it will not work.

That form looks like this:

let longString = "This is a very long string which needs \
to wrap across multiple lines because \
otherwise my code is unreadable."
					

Both of the above methods result in identical strings.

构造函数

String()
创建新的 String object. It performs type conversion when called as a function, rather than as a constructor, which is usually more useful.

静态方法

String.fromCharCode( num1 [, ...[, numN ]])
Returns a string created by using the specified sequence of Unicode values.
String.fromCodePoint( num1 [, ...[, numN )
Returns a string created by using the specified sequence of code points.
String.raw()
Returns a string created from a raw template string.

实例特性

String.prototype.length
Reflects the length of the string. Read-only.

实例方法

String.prototype.charAt( index )
Returns the character (exactly one UTF-16 code unit) at the specified index .
String.prototype.charCodeAt( index )
Returns a number that is the UTF-16 code unit value at the given index .
String.prototype.codePointAt( pos )
Returns a nonnegative integer Number that is the code point value of the UTF-16 encoded code point starting at the specified pos .
String.prototype.concat( str [, ... strN ])
Combines the text of two (or more) strings and returns a new string.
String.prototype.includes( searchString [, position ])
Determines whether the calling string contains searchString .
String.prototype.endsWith( searchString [, length ])
Determines whether a string ends with the characters of the string searchString .
String.prototype.indexOf( searchValue [, fromIndex ])
Returns the index within the calling String object of the first occurrence of searchValue ,或 -1 if not found.
String.prototype.lastIndexOf( searchValue [, fromIndex ])
Returns the index within the calling String object of the last occurrence of searchValue ,或 -1 if not found.
String.prototype.localeCompare( compareString [, locales [, options ]])
Returns a number indicating whether the reference string compareString comes before, after, or is equivalent to the given string in sort order.
String.prototype.match( regexp )
Used to match regular expression regexp 与字符串。
String.prototype.matchAll( regexp )
Returns an iterator of all regexp 's matches.
String.prototype.normalize([ form ])
Returns the Unicode Normalization Form of the calling string value.
String.prototype.padEnd( targetLength [, padString ])
Pads the current string from the end with a given string and returns a new string of the length targetLength .
String.prototype.padStart( targetLength [, padString ])
Pads the current string from the start with a given string and returns a new string of the length targetLength .
String.prototype.repeat( count )
Returns a string consisting of the elements of the object repeated count times.
String.prototype.replace( searchFor , replaceWith )
Used to replace occurrences of searchFor 使用 replaceWith . searchFor may be a string or Regular Expression, and replaceWith may be a string or function.
String.prototype.replaceAll( searchFor , replaceWith )
Used to replace all occurrences of searchFor 使用 replaceWith . searchFor may be a string or Regular Expression, and replaceWith may be a string or function.
String.prototype.search( regexp )
Search for a match between a regular expression regexp and the calling string.
String.prototype.slice( beginIndex [, endIndex ])
Extracts a section of a string and returns a new string.
String.prototype.split([ sep [, limit ] ])
Returns an array of strings populated by splitting the calling string at occurences of the substring sep .
String.prototype.startsWith( searchString [, length ])
Determines whether the calling string begins with the characters of string searchString .
String.prototype.substr()
Returns the characters in a string beginning at the specified location through the specified number of characters.
String.prototype.substring( indexStart [, indexEnd ])
Returns a new string containing characters of the calling string from (or between) the specified index (or indeces).
String.prototype.toLocaleLowerCase( [ locale , ... locales ])

The characters within a string are converted to lowercase while respecting the current locale.

For most languages, this will return the same as toLowerCase() .

String.prototype.toLocaleUpperCase( [ locale , ... locales ])

The characters within a string are converted to uppercase while respecting the current locale.

For most languages, this will return the same as toUpperCase() .

String.prototype.toLowerCase()
Returns the calling string value converted to lowercase.
String.prototype.toString()
Returns a string representing the specified object. Overrides the Object.prototype.toString() 方法。
String.prototype.toUpperCase()
Returns the calling string value converted to uppercase.
String.prototype.trim()
Trims whitespace from the beginning and end of the string. Part of the ECMAScript 5 standard.
String.prototype.trimStart()
Trims whitespace from the beginning of the string.
String.prototype.trimEnd()
Trims whitespace from the end of the string.
String.prototype.valueOf()
Returns the primitive value of the specified object. Overrides the Object.prototype.valueOf() 方法。
String.prototype.@@iterator()
返回新 Iterator object that iterates over the code points of a String value, returning each code point as a String value.

HTML wrapper methods

Deprecated. Avoid these methods.

They are of limited use, as they provide only a subset of the available HTML tags and attributes.

String.prototype.anchor()
<a name="name"> (hypertext target)
String.prototype.big()
<big>
String.prototype.blink()
<blink>
String.prototype.bold()
<b>
String.prototype.fixed()
<tt>
String.prototype.fontcolor()
<font color="color">
String.prototype.fontsize()
<font size="size">
String.prototype.italics()
<i>
String.prototype.link()
<a href="url"> (link to URL)
String.prototype.small()
<small>
String.prototype.strike()
<strike>
String.prototype.sub()
<sub>
String.prototype.sup()
<sup>

范例

String conversion

It's possible to use String as a more reliable toString() alternative, as it works when used on null , undefined , and on symbols 。例如:

let outputStrings = []
for (let i = 0, n = inputValues.length; i < n; ++i) {
  outputStrings.push(String(inputValues[i]));
}
					

规范

规范
ECMAScript (ECMA-262)
The definition of 'String' in that specification.

浏览器兼容性

更新 GitHub 上的兼容性数据
Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet Node.js
String Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
String() 构造函数 Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
anchor
弃用
Chrome 1 Edge 12 Firefox 1
1
Starting with version 17, the quotation mark (") is replaced by its HTML reference character ( " ) in strings supplied for the name 参数。
IE No Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
big
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
blink
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
bold
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
charAt Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
charCodeAt Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
codePointAt Chrome 41 Edge 12 Firefox 29 IE No Opera 28 Safari 10 WebView Android 41 Chrome Android 41 Firefox Android 29 Opera Android 28 Safari iOS 10 Samsung Internet Android 4.0 nodejs 4.0.0
4.0.0
0.12
Disabled
Disabled From version 0.12: this feature is behind the --harmony runtime flag.
concat Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
endsWith Chrome 41 Edge 12 Firefox 17 IE No Opera 28 Safari 9 WebView Android ≤37 Chrome Android 36 Firefox Android 17 Opera Android 24 Safari iOS 9 Samsung Internet Android 3.0 nodejs 4.0.0
4.0.0
0.12
Disabled
Disabled From version 0.12: this feature is behind the --harmony runtime flag.
fixed
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
fontcolor
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
fontsize
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
fromCharCode Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
fromCodePoint Chrome 41 Edge 12 Firefox 29 IE No Opera 28 Safari 10 WebView Android 41 Chrome Android 41 Firefox Android 29 Opera Android 28 Safari iOS 10 Samsung Internet Android 4.0 nodejs 4.0.0
4.0.0
0.12
Disabled
Disabled From version 0.12: this feature is behind the --harmony runtime flag.
includes Chrome 41 Edge 12 Firefox 40
40
不支持 18 — 48
Alternate Name
Alternate Name Uses the non-standard name: contains
IE No Opera 28 Safari 9 WebView Android 41 Chrome Android 41 Firefox Android 40
40
不支持 18 — 48
Alternate Name
Alternate Name Uses the non-standard name: contains
Opera Android 28 Safari iOS 9 Samsung Internet Android 4.0 nodejs 4.0.0
indexOf Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
italics
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
lastIndexOf Chrome 1 Edge 12 Firefox 1 IE 6 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
length Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
link
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
localeCompare Chrome 1 Edge 12 Firefox 1 IE 5.5 Opera 7 Safari 3 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
match Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
matchAll Chrome 73 Edge 79 Firefox 67 IE No Opera 60 Safari 13 WebView Android 73 Chrome Android 73 Firefox Android 67 Opera Android 52 Safari iOS 13 Samsung Internet Android No nodejs 12.0.0
normalize Chrome 34 Edge 12 Firefox 31 IE No Opera 21 Safari 10 WebView Android No Chrome Android 34 Firefox Android 31 Opera Android 21 Safari iOS 10 Samsung Internet Android 2.0 nodejs 0.12
padEnd Chrome 57 Edge 15 Firefox 48 IE No Opera 44 Safari 10 WebView Android 57 Chrome Android 57 Firefox Android 48 Opera Android 43 Safari iOS 10 Samsung Internet Android 7.0 nodejs 8.0.0
8.0.0
7.0.0
Disabled
Disabled From version 7.0.0: this feature is behind the --harmony runtime flag.
padStart Chrome 57 Edge 15 Firefox 48 IE No Opera 44 Safari 10 WebView Android 57 Chrome Android 57 Firefox Android 48 Opera Android 43 Safari iOS 10 Samsung Internet Android 7.0 nodejs 8.0.0
8.0.0
7.0.0
Disabled
Disabled From version 7.0.0: this feature is behind the --harmony runtime flag.
raw Chrome 41 Edge 12 Firefox 34 IE No Opera No Safari 10 WebView Android No Chrome Android 41 Firefox Android 34 Opera Android No Safari iOS 10 Samsung Internet Android 4.0 nodejs 4.0.0
repeat Chrome 41 Edge 12 Firefox 24 IE No Opera 28 Safari 9 WebView Android No Chrome Android 36 Firefox Android 24 Opera Android 28 Safari iOS 9 Samsung Internet Android 3.0 nodejs 4.0.0
4.0.0
0.12
Disabled
Disabled From version 0.12: this feature is behind the --harmony runtime flag.
replace Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
replaceAll Chrome 85 Edge No Firefox 77 IE No Opera No Safari 13.1 WebView Android 85 Chrome Android 85 Firefox Android No Opera Android No Safari iOS 13.4 Samsung Internet Android No nodejs No
search Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
slice Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
small
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
split Chrome 1 Edge 12 Firefox 1 IE 4 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
startsWith Chrome 41 Edge 12 Firefox 17 IE No Opera 28 Safari 9 WebView Android ≤37 Chrome Android 36 Firefox Android 17 Opera Android 24 Safari iOS 9 Samsung Internet Android 3.0 nodejs 4.0.0
4.0.0
0.12
Disabled
Disabled From version 0.12: this feature is behind the --harmony runtime flag.
strike
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
sub
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
substr
弃用
Chrome 1 Edge 12 Firefox 1 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
substring Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
sup
弃用
Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
toLocaleLowerCase Chrome 1 Edge 12 Firefox 1 IE 5.5 Opera 4 Safari 1.3 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
toLocaleUpperCase Chrome 1 Edge 12 Firefox 1 IE 5.5 Opera 4 Safari 1.3 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
toLowerCase Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
toSource
非标
Chrome No Edge No Firefox 1 — 74
不支持 1 — 74
Starting in Firefox 74, toSource() is no longer available for use by web content. It is still allowed for internal and privileged code.
IE No Opera No Safari No WebView Android No Chrome Android No Firefox Android 4 Opera Android No Safari iOS No Samsung Internet Android No nodejs No
toString Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
toUpperCase Chrome 1 Edge 12 Firefox 1 IE 3 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
trim Chrome 4 Edge 12 Firefox 3.5 IE 9 Opera 10.5 Safari 5 WebView Android ≤37 Chrome Android 18 Firefox Android 4 Opera Android 11 Safari iOS 5 Samsung Internet Android 1.0 nodejs 0.1.100
trimEnd Chrome 66
66
4
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Edge 12
Alternate Name
12
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Firefox 61
61
3.5
Alternate Name
Alternate Name Uses the non-standard name: trimRight
IE No Opera 53
53
15
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Safari 12 WebView Android 66
66
≤37
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Chrome Android 66
66
18
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Firefox Android 61
61
4
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Opera Android 47
47
14
Alternate Name
Alternate Name Uses the non-standard name: trimRight
Safari iOS 12 Samsung Internet Android 9.0
9.0
1.0
Alternate Name
Alternate Name Uses the non-standard name: trimRight
nodejs 10.0.0
10.0.0
0.12
Alternate Name
Alternate Name Uses the non-standard name: trimRight
trimStart Chrome 66
66
4
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Edge 12
Alternate Name
12
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Firefox 61
61
3.5
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
IE No Opera 53
53
15
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Safari 12 WebView Android 66
66
≤37
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Chrome Android 66
66
18
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Firefox Android 61
61
4
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Opera Android 47
47
14
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Safari iOS 12 Samsung Internet Android 9.0
9.0
1.0
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
nodejs 10.0.0
10.0.0
0.12
Alternate Name
Alternate Name Uses the non-standard name: trimLeft
Unicode code point escapes \u{xxxxxx} Chrome 1 Edge 12 Firefox 40 IE 4 Opera 4 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 40 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
valueOf Chrome 1 Edge 12 Firefox 1 IE 4 Opera 3 Safari 1 WebView Android 1 Chrome Android 18 Firefox Android 4 Opera Android 10.1 Safari iOS 1 Samsung Internet Android 1.0 nodejs 0.1.100
@@iterator Chrome 38 Edge 12 Firefox 36
36
不支持 27 — 36
Alternate Name
A placeholder property named @@iterator 被使用。
Alternate Name Uses the non-standard name: @@iterator
不支持 17 — 27
Alternate Name
A placeholder property named iterator 被使用。
Alternate Name Uses the non-standard name: iterator
IE No Opera 25 Safari No WebView Android 38 Chrome Android 38 Firefox Android 36
36
不支持 27 — 36
Alternate Name
A placeholder property named @@iterator 被使用。
Alternate Name Uses the non-standard name: @@iterator
不支持 17 — 27
Alternate Name
A placeholder property named iterator 被使用。
Alternate Name Uses the non-standard name: iterator
Opera Android 25 Safari iOS No Samsung Internet Android 3.0 nodejs 0.12

图例

完整支持
完整支持
不支持
不支持
非标。预期跨浏览器支持较差。
非标。预期跨浏览器支持较差。
弃用。不要用于新网站。
弃用。不要用于新网站。
见实现注意事项。
用户必须明确启用此特征。
用户必须明确启用此特征。
使用非标名称。

另请参阅

Metadata

  1. 标准内置对象
  2. String
  3. 特性
    1. String length
  4. 方法
    1. String.fromCharCode()
    2. String.fromCodePoint()
    3. String.prototype.anchor()
    4. String.prototype.big()
    5. String.prototype.blink()
    6. String.prototype.bold()
    7. String.prototype.charAt()
    8. String.prototype.charCodeAt()
    9. String.prototype.codePointAt()
    10. String.prototype.concat()
    11. String.prototype.endsWith()
    12. String.prototype.fixed()
    13. String.prototype.fontcolor()
    14. String.prototype.fontsize()
    15. String.prototype.includes()
    16. String.prototype.indexOf()
    17. String.prototype.italics()
    18. String.prototype.lastIndexOf()
    19. String.prototype.link()
    20. String.prototype.localeCompare()
    21. String.prototype.match()
    22. String.prototype.matchAll()
    23. String.prototype.normalize()
    24. String.prototype.padEnd()
    25. String.prototype.padStart()
    26. String.prototype.repeat()
    27. String.prototype.replace()
    28. String.prototype.replaceAll()
    29. String.prototype.search()
    30. String.prototype.slice()
    31. String.prototype.small()
    32. String.prototype.split()
    33. String.prototype.startsWith()
    34. String.prototype.strike()
    35. String.prototype.sub()
    36. String.prototype.substr()
    37. String.prototype.substring()
    38. String.prototype.sup()
    39. String.prototype.toLocaleLowerCase()
    40. String.prototype.toLocaleUpperCase()
    41. String.prototype.toLowerCase()
    42. String.prototype.toSource()
    43. String.prototype.toString()
    44. String.prototype.toUpperCase()
    45. String.prototype.trim()
    46. String.prototype.trimEnd()
    47. String.prototype.trimStart()
    48. String.prototype.valueOf()
    49. String.prototype[@@iterator]()
    50. String.raw()
  5. 继承:
  6. Function
  7. 特性
    1. Function.arguments
    2. Function.caller
    3. Function.displayName
    4. Function.length
    5. Function.name
  8. 方法
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.toSource()
    5. Function.prototype.toString()
  9. Object
  10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
  11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()