Core JavaScript 1.5 Reference:Global Objects:String:prototype
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[edit] Summary
Represents the String prototype object.
[edit] Description
All String instances inherit from String.prototype. Changes to the String prototype object are propagated to all String instances.
[edit] Properties
- constructor
- Specifies the function that creates an object's prototype.
- length
- Reflects the length of the string.
- N
- Non-standard
- Used to access the character in the Nth position where N is a positive integer between 0 and one less than the value of length. These properties are read-only.
[edit] Methods
[edit] Methods unrelated to HTML
- charAt
- Returns the character at the specified index.
- charCodeAt
- Returns a number indicating the Unicode value of the character at the given index.
- concat
- Combines the text of two strings and returns a new string.
- indexOf
- Returns the index within the calling String object of the first occurrence of the specified value, or -1 if not found.
- lastIndexOf
- Returns the index within the calling String object of the last occurrence of the specified value, or -1 if not found.
- localeCompare
- Returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.
- match
- Used to match a regular expression against a string.
- quote
- Non-standard
- Wraps the string in double quotes ("
"").
- replace
- Used to find a match between a regular expression and a string, and to replace the matched substring with a new substring.
- search
- Executes the search for a match between a regular expression and a specified string.
- slice
- Extracts a section of a string and returns a new string.
- split
- Splits a String object into an array of strings by separating the string into substrings.
- substr
- Returns the characters in a string beginning at the specified location through the specified number of characters.
- substring
- Returns the characters in a string between two indexes into the string.
- toLocaleLowerCase
- The characters within a string are converted to lower case while respecting the current locale. For most languages, this will return the same as toLowerCase.
- toLocaleUpperCase
- The characters within a string are converted to upper case while respecting the current locale. For most languages, this will return the same as toUpperCase.
- toLowerCase
- Returns the calling string value converted to lower case.
- toSource
- Non-standard
- Returns an object literal representing the specified object; you can use this value to create a new object. Overrides the Object.toSource method.
- toString
- Returns a string representing the specified object. Overrides the Object.toString method.
- toUpperCase
- Returns the calling string value converted to uppercase.
- valueOf
- Returns the primitive value of the specified object. Overrides the Object.valueOf method.
[edit] HTML wrapper methods
Non-standard
Each of the following methods returns a copy of the string wrapped inside the appropriate HTML tag.
- anchor
-
<a name="name">(hypertext target)
- blink
-
<blink>
- fontcolor
-
<font color="color">
- fontsize
-
<font size="size">
- link
-
<a href="url">(link to URL)
These methods are of limited use, as they provide only a subset of the available HTML tags and attributes.
Methods inherited from Object.prototype
__defineGetter__, __defineSetter__, hasOwnProperty, isPrototypeOf, __lookupGetter__, __lookupSetter__, __noSuchMethod__, propertyIsEnumerable, unwatch, watch
[edit] Examples
[edit] Example: Extending string instances with a repeat method
The following example creates a method, str_rep, and uses the statement String.prototype.repeat = str_rep to add the method to all String objects. All String instances then have that method, even objects already created. The example then creates an alternate method and overrides the previous method in one of the String objects using the statement s1.repeat = fake_rep. The str_rep method of the remaining String objects is not altered.
var s1 = new String("a");
var s2 = new String("b");
var s3 = new String("c");
// Create a repeat-string-N-times method for all String objects
function str_rep(n) {
var s = "", t = this.toString();
while (--n >= 0) {
s += t
}
return s;
}
String.prototype.repeat = str_rep;
s1a=s1.repeat(3); // returns "aaa"
s2a=s2.repeat(5); // returns "bbbbb"
s3a=s3.repeat(2); // returns "cc"
// Create an alternate method and assign it to only one String variable
function fake_rep(n) {
return "repeat " + this + " " + n + " times.";
}
s1.repeat = fake_rep
s1b=s1.repeat(1); // returns "repeat a 1 times."
s2b=s2.repeat(4); // returns "bbbb"
s3b=s3.repeat(6); // returns "cccccc"
The function in this example also works on String objects not created with the String constructor. The following code returns "zzz".
"z".repeat(3);