String

创建源

new String(string);

参数

描述

A string can be represented as a literal enclosed by single or double quotation marks; for example, "Netscape" or 'Netscape'.

属性概览

方法概览

示例

var last_name = "Schaefer" 示例 2: String object properties. The following statements evaluate to 8, "SCHAEFER," and "schaefer":

last_name.length
last_name.toUpperCase()
last_name.toLowerCase() 示例 3: Accessing individual characters in a string. You can think of a string as an array of characters. In this way, you can access the individual characters in the string by indexing that array. For example, the following code:

var myString = "Hello"
document.write ("The first character in the string is " + myString[0]) displays "The first character in the string is H"

示例 4: Pass a string among scripts in different windows or frames. The following code creates two string variables and opens a second window:

var lastName = new String("Schaefer")
var firstName = new String ("Jesse")
empWindow=window.open('string2.html','window1','width=300,height=300') If the HTML source for the second window (string2.html) creates two string variables, empLastName and empFirstName, the following code in the first window assigns values to the second window's variables:

empWindow.empFirstName=firstName
empWindow.empLastName=lastName The following code in the first window displays the values of the second window's variables:

alert('empFirstName in empWindow is ' + empWindow.empFirstName)
alert('empLastName in empWindow is ' + empWindow.empLastName)

属性

描述

示例

var x="Netscape"
alert("The string length is " + x.length)

prototype

方法

语法

描述

In the语法, the text string represents the literal text that you want the user to see. The nameAttribute string represents the NAME attribute of the A tag.

Anchors created with the anchor method become elements in the document.anchors array.

示例

var myString="表 of Contents"
msgWindow.document.writeln(myString.anchor("contents_anchor")) The previous example produces the same output as the following HTML:

<A NAME="contents_anchor">表 of Contents</A> In server-side JavaScript, you can generate this HTML by calling the write function instead of using document.writeln.

参看

big

语法

描述

示例

var worldString="Hello, world" document.write(worldString.small())
document.write("<P>" + worldString.big())
document.write("<P>" + worldString.fontsize(7)) The previous example produces the same output as the following HTML:

<SMALL>Hello, world</SMALL>
<P><BIG>Hello, world</BIG>
<P><FONTSIZE=7>Hello, world</FONTSIZE>

参看

blink

语法

描述

示例

var worldString="Hello, world" document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike()) The previous example produces the same output as the following HTML:

<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>

参看

bold

语法

描述

示例

var worldString="Hello, world"
document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike()) The previous example produces the same output as the following HTML:

<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>

参看

charAt

语法

描述

示例

var anyString="Brave new world" document.writeln("The character at index 0 is " + anyString.charAt(0))
document.writeln("The character at index 1 is " + anyString.charAt(1))
document.writeln("The character at index 2 is " + anyString.charAt(2))
document.writeln("The character at index 3 is " + anyString.charAt(3))
document.writeln("The character at index 4 is " + anyString.charAt(4)) These lines display the following:

The character at index 0 is B
The character at index 1 is r
The character at index 2 is a
The character at index 3 is v
The character at index 4 is e

In server-side JavaScript, you can display the same output by calling the write function instead of using document.write.

参看

charCodeAt

语法

描述

示例

"ABC".charCodeAt(0)

concat

语法

描述

示例

<SCRIPT>
str1="The morning is upon us. "
str2="The sun is bright."
str3=str1.concat(str2)
document.writeln(str1)
document.writeln(str2)
document.writeln(str3)
</SCRIPT> This writes:

The morning is upon us.
The sun is bright.
The morning is upon us. The sun is bright.

fixed

语法

描述

示例

var worldString="Hello, world"
document.write(worldString.fixed()) The previous example produces the same output as the following HTML:

<TT>Hello, world</TT>

fontcolor

语法

描述

If you express color as a hexadecimal RGB triplet, you must use the format rrggbb. For example, the hexadecimal RGB values for salmon are red=FA, green=80, and blue=72, so the RGB triplet for salmon is "FA8072".

The fontcolor method overrides a value set in the fgColor property.

示例

var worldString="Hello, world" document.write(worldString.fontcolor("maroon") +
   " is maroon in this line")
document.write("<P>" + worldString.fontcolor("salmon") +
   " is salmon in this line")
document.write("<P>" + worldString.fontcolor("red") +
   " is red in this line") document.write("<P>" + worldString.fontcolor("8000") +
   " is maroon in hexadecimal in this line")
document.write("<P>" + worldString.fontcolor("FA8072") +
   " is salmon in hexadecimal in this line")
document.write("<P>" + worldString.fontcolor("FF00") +
   " is red in hexadecimal in this line") The previous example produces the same output as the following HTML:

<FONT COLOR="maroon">Hello, world</FONT> is maroon in this line
<P><FONT COLOR="salmon">Hello, world</FONT> is salmon in this line
<P><FONT COLOR="red">Hello, world</FONT> is red in this line <FONT COLOR="8000">Hello, world</FONT>
is maroon in hexadecimal in this line
<P><FONT COLOR="FA8072">Hello, world</FONT>
is salmon in hexadecimal in this line
<P><FONT COLOR="FF00">Hello, world</FONT>
is red in hexadecimal in this line

fontsize

语法

描述

When you specify size as an integer, you set the size of stringName to one of the 7 defined sizes. When you specify size as a string such as "-2", you adjust the font size of stringName relative to the size set in the BASEFONT tag.

示例

var worldString="Hello, world" document.write(worldString.small())
document.write("<P>" + worldString.big())
document.write("<P>" + worldString.fontsize(7)) The previous example produces the same output as the following HTML:

<SMALL>Hello, world</SMALL>
<P><BIG>Hello, world</BIG>
<P><FONTSIZE=7>Hello, world</FONTSIZE>

参看

fromCharCode

语法

描述

Because fromCharCode is a static method of String, you always use it as String.fromCharCode(), rather than as a method of a String object you created.

示例

String.fromCharCode(65,66,67) 示例 2. The which property of the KeyDown, KeyPress, and KeyUp events contains the ASCII value of the key pressed at the time the event occurred. If you want to get the actual letter, number, or symbol of the key, you can use fromCharCode. The following example returns the letter, number, or symbol of the KeyPress event's which property.

String.fromCharCode(KeyPress.which)

indexOf

语法

描述

If stringName contains an empty string (""), indexOf returns an empty string.

The indexOf method is case sensitive. For example, the following expression returns -1:

"Blue Whale".indexOf("blue")

示例

var anyString="Brave new world" //Displays 8
document.write("<P>The index of the first w from the beginning is " +
   anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
   anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
   anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
   anyString.lastIndexOf("new")) 示例 2. The following example defines two string variables. The variables contain the same string except that the second string contains uppercase letters. The first writeln method displays 19. But because the indexOf method is case sensitive, the string "cheddar" is not found in myCapString, so the second writeln method displays -1.

myString="brie, pepper jack, cheddar"
myCapString="Brie, Pepper Jack, Cheddar"
document.writeln('myString.indexOf("cheddar") is ' +
   myString.indexOf("cheddar"))
document.writeln('<P>myCapString.indexOf("cheddar") is ' +
   myCapString.indexOf("cheddar")) 示例 3. The following example sets count to the number of occurrences of the letter x in the string str:

count = 0;
pos = str.indexOf("x");
while ( pos != -1 ) {
   count++;
   pos = str.indexOf("x",pos+1);
}

参看

italics

语法

描述

示例

var worldString="Hello, world" document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike()) The previous example produces the same output as the following HTML:

<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>

参看

lastIndexOf

语法

描述

The lastIndexOf method is case sensitive. For example, the following expression returns -1:

"Blue Whale, Killer Whale".lastIndexOf("blue")

示例

var anyString="Brave new world" //Displays 8
document.write("<P>The index of the first w from the beginning is " +
   anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
   anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
   anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
   anyString.lastIndexOf("new")) In server-side JavaScript, you can display the same output by calling the write function instead of using document.write.

参看

link

语法

描述

Links created with the link method become elements in the links array of the document object. See document.links.

示例

var hotText="Netscape"
var URL="http://home.netscape.com" document.write("Click to return to " + hotText.link(URL)) The previous example produces the same output as the following HTML:

Click to return to <A HREF="http://home.netscape.com">Netscape</A>

参看

match

语法

描述

Note

示例

<SCRIPT>
str = "For more information, see Chapter 3.4.5.1";
re = /(chapter \d+(\.\d)*)/i;
found = str.match(re);
document.write(found);
</SCRIPT> This returns the array containing Chapter 3.4.5.1,Chapter 3.4.5.1,.1

'Chapter 3.4.5.1' is the first match and the first value remembered from (Chapter \d+(\.\d)*).

'.1' is the second value remembered from (\.\d).

示例 2. The following example demonstrates the use of the global and ignore case flags with match.

<SCRIPT>
str = "abcDdcba";
newArray = str.match(/d/gi);
document.write(newArray);
</SCRIPT> The returned array contains D, d.

replace

语法

描述

If you want to execute a global search and replace, or a case insensitive search, include the g (for global) and i (for ignore case) flags in the regular expression. These can be included separately or together. The following two示例 below show how to use these flags with replace.

示例

<SCRIPT>
re = /apples/gi;
str = "Apples are round, and apples are juicy.";
newstr=str.replace(re, "oranges");
document.write(newstr)
</SCRIPT> This prints "oranges are round, and oranges are juicy."

示例 2. In the following example, the regular expression is defined in replace and includes the ignore case flag.

<SCRIPT>
str = "Twas the night before Xmas...";
newstr=str.replace(/xmas/i, "Christmas");
document.write(newstr)
</SCRIPT> This prints "Twas the night before Christmas..."

示例 3. The following script switches the words in the string. For the replacement text, the script uses the values of the $1 and $2 properties.

<SCRIPT LANGUAGE="JavaScript1.2">
re = /(\w+)\s(\w+)/;
str = "John Smith";
newstr = str.replace(re, "$2, $1");
document.write(newstr)
</SCRIPT> This prints "Smith, John".

search

语法

描述

When you want to know whether a pattern is found in a string use search (similar to the regular expression test method); for more information (but slower execution) use match (similar to the regular expression exec method).

示例

function testinput(re, str){
   if (str.search(re) != -1)
      midstring = " contains ";
   else
      midstring = " does not contain ";
   document.write (str + midstring + re.source);
}

slice

语法

描述

slice extracts up to but not including endSlice. string.slice(1,4) extracts the second character through the fourth character (characters indexed 1, 2, and 3).

As a negative index, endSlice indicates an offset from the end of the string. string.slice(2,-1) extracts the third character through the second to last character in the string.

示例

<SCRIPT>
str1="The morning is upon us. "
str2=str1.slice(3,-5)
document.write(str2)
</SCRIPT> This writes:

morning is upon

small

语法

描述

示例

var worldString="Hello, world" document.write(worldString.small())
document.write("<P>" + worldString.big())
document.write("<P>" + worldString.fontsize(7)) The previous example produces the same output as the following HTML:

<SMALL>Hello, world</SMALL>
<P><BIG>Hello, world</BIG>
<P><FONTSIZE=7>Hello, world</FONTSIZE>

参看

split

语法

描述

When found, separator is removed from the string and the substrings are returned in an array. If separator is omitted, the array contains one element consisting of the entire string.

In Navigator 4.0, Split has the following additions:

• It can take a regular expression argument, as well as a fixed string, by which to split the object string. If separator is a regular expression, any included parenthesis cause submatches to be included in the returned array.
• It can take a limit count so that it won't include trailing empty elements in the resulting array.
• If you specify LANGUAGE="JavaScript1.2" in the SCRIPT tag, string.split(" ") splits on any run of 1 or more white space characters including spaces, tabs, line feeds, and carriage returns.

function splitString (stringToSplit,separator) {
   arrayOfStrings = stringToSplit.split(separator)
   document.write ('<P>The original string is: "' + stringToSplit + '"')
   document.write ('<BR>The separator is: "' + separator + '"')
   document.write ("<BR>The array has " + arrayOfStrings.length + " elements: ")    for (var i=0; i < arrayOfStrings.length; i++) {
      document.write (arrayOfStrings[i] + " / ")
   }
} var tempestString="Oh brave new world that has such people in it."
var monthString="Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec" var space=" "
var comma="," splitString(tempestString,space)
splitString(tempestString)
splitString(monthString,comma) This example produces the following output:

The original string is: "Oh brave new world that has such people in it."
The separator is: " "
The array has 10 elements: Oh / brave / new / world / that / has / such / people / in / it. / The original string is: "Oh brave new world that has such people in it."
The separator is: "undefined"
The array has 1 elements: Oh brave new world that has such people in it. / The original string is: "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec"
The separator is: ","
The array has 12 elements: Jan / Feb / Mar / Apr / May / Jun / Jul / Aug / Sep / Oct / Nov / Dec / 示例 2. Consider the following script:

<SCRIPT LANGUAGE="JavaScript1.2">
str="She sells seashells \nby the\n seashore"
document.write(str + "<BR>")
a=str.split(" ")
document.write(a)
</SCRIPT> Using LANGUAGE="JavaScript1.2", this script produces

"She", "sells", "seashells", "by", "the", "seashore" Without LANGUAGE="JavaScript1.2", this script splits only on single space characters, producing

"She", "sells", , , , "seashells", "by", , , "the", "seashore" 示例 3. In the following example, split looks for 0 or more spaces followed by a semicolon followed by 0 or more spaces and, when found, removes the spaces from the string. nameList is the array returned as a result of split.

<SCRIPT>
names = "Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand ";
document.write (names + "<BR>" + "<BR>");
re = /\s*;\s*/;
nameList = names.split (re);
document.write(nameList);
</SCRIPT> This prints two lines; the first line prints the original string, and the second line prints the resulting array.

Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand
Harry Trump,Fred Barney,Helen Rigby,Bill Abel,Chris Hand

示例 4. In the following example, split looks for 0 or more spaces in a string and returns the first 3 splits that it finds.

<SCRIPT LANGUAGE="JavaScript1.2">
myVar = " Hello World. How are you doing? ";
splits = myVar.split(" ", 3);
document.write(splits)
</SCRIPT> This script displays the following:

["Hello", "World.", "How"]

参看

strike

语法

描述

示例

var worldString="Hello, world" document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike()) The previous example produces the same output as the following HTML:

<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>

参看

sub

语法

描述

示例

var superText="superscript"
var subText="subscript" document.write("This is what a " + superText.sup() + " looks like.")
document.write("<P>This is what a " + subText.sub() + " looks like.") The previous example produces the same output as the following HTML:

This is what a <SUP>superscript</SUP> looks like.
<P>This is what a <SUB>subscript</SUB> looks like.

参看

substr

语法

描述

If start is positive and is the length of the string or longer, substr returns no characters.

If start is negative, substr uses it as a character index from the end of the string. If start is negative and abs(start) is larger than the length of the string, substr uses 0 is the start index.

If length is 0 or negative, substr returns no characters. If length is omitted, start extracts characters to the end of the string.

示例

<SCRIPT LANGUAGE="JavaScript1.2"> str = "abcdefghij"
document.writeln("(1,2): ", str.substr(1,2))
document.writeln("(-2,2): ", str.substr(-2,2))
document.writeln("(1): ", str.substr(1))
document.writeln("(-20, 2): ", str.substr(1,20))
document.writeln("(20, 2): ", str.substr(20,2)) </SCRIPT> This script displays:

(1,2): bc
(-2,2): ij
(1): bcdefghij
(-20, 2): bcdefghij
(20, 2):

参看

substring

语法

描述

• If indexA is less than 0, indexA is treated as if it were 0.
• If indexB is greater than stringName.length, indexB is treated as if it were stringName.length.
• If indexA equals indexB, substring returns an empty string.
• If indexB is omitted, indexA extracts characters to the end of the string.

• If indexA is greater than indexB, JavaScript produces a runtime error (out of memory).

• If indexA is greater than indexB, JavaScript returns a substring beginning with indexB and ending with indexA - 1.

var anyString="Netscape" //Displays "Net"
document.write(anyString.substring(0,3))
document.write(anyString.substring(3,0))
//Displays "cap"
document.write(anyString.substring(4,7))
document.write(anyString.substring(7,4))
//Displays "Netscap"
document.write(anyString.substring(0,7))
//Displays "Netscape"
document.write(anyString.substring(0,8))
document.write(anyString.substring(0,10)) 示例 2. The following example replaces a substring within a string. It will replace both individual characters and substrings. The function call at the end of the example changes the string "Brave New World" into "Brave New Web".

function replaceString(oldS,newS,fullS) {
// Replaces oldS with newS in the string fullS
   for (var i=0; i<fullS.length; i++) {
      if (fullS.substring(i,i+oldS.length) == oldS) {
         fullS = fullS.substring(0,i)+newS+fullS.substring(i+oldS.length,fullS.length)
      }
   }
   return fullS
} replaceString("World","Web","Brave New World") 示例 3. Using LANGUAGE="JavaScript1.2", the following script produces a runtime error (out of memory).

<SCRIPT LANGUAGE="JavaScript1.2">
str="Netscape"
document.write(str.substring(0,3);
document.write(str.substring(3,0);
</SCRIPT> Without LANGUAGE="JavaScript1.2", the above script prints

Net Net

In the second write, the index numbers are swapped.

参看

sup

语法

描述

示例

var superText="superscript"
var subText="subscript" document.write("This is what a " + superText.sup() + " looks like.")
document.write("<P>This is what a " + subText.sub() + " looks like.") The previous example produces the same output as the following HTML:

This is what a <SUP>superscript</SUP> looks like.
<P>This is what a <SUB>subscript</SUB> looks like.

参看

toLowerCase

语法

描述

示例

var upperText="ALPHABET"
document.write(upperText.toLowerCase())

参看

toUpperCase

语法

描述

示例

var lowerText="alphabet"
document.write(lowerText.toUpperCase())

参看