JavaScript - Đối tượng chuỗi

Các Stringđối tượng cho phép bạn làm việc với một loạt các ký tự; nó bao bọc kiểu dữ liệu nguyên thủy chuỗi của Javascript với một số phương thức trợ giúp.

Vì JavaScript tự động chuyển đổi giữa các nguyên thủy chuỗi và các đối tượng Chuỗi, bạn có thể gọi bất kỳ phương thức trợ giúp nào của đối tượng Chuỗi trên một nguyên thủy chuỗi.

Cú pháp

Sử dụng cú pháp sau để tạo một đối tượng Chuỗi:

var val = new String(string);

Các String tham số là một loạt các ký tự đã được mã hóa đúng cách.

Thuộc tính chuỗi

Đây là danh sách các thuộc tính của đối tượng String và mô tả của chúng.

Sr.No.	Kê khai tài sản
1	constructor Returns a reference to the String function that created the object.
2	length Returns the length of the string.
3	prototype The prototype property allows you to add properties and methods to an object.

In the following sections, we will have a few examples to demonstrate the usage of String properties.

String Methods

Here is a list of the methods available in String object along with their description.

Sr.No.	Method & Description
1	charAt() Returns the character at the specified index.
2	charCodeAt() Returns a number indicating the Unicode value of the character at the given index.
3	concat() Combines the text of two strings and returns a new string.
4	indexOf() Returns the index within the calling String object of the first occurrence of the specified value, or -1 if not found.
5	lastIndexOf() Returns the index within the calling String object of the last occurrence of the specified value, or -1 if not found.
6	localeCompare() Returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.
7	match() Used to match a regular expression against a string.
8	replace() Used to find a match between a regular expression and a string, and to replace the matched substring with a new substring.
9	search() Executes the search for a match between a regular expression and a specified string.
10	slice() Extracts a section of a string and returns a new string.
11	split() Splits a String object into an array of strings by separating the string into substrings.
12	substr() Returns the characters in a string beginning at the specified location through the specified number of characters.
13	substring() Returns the characters in a string between two indexes into the string.
14	toLocaleLowerCase() The characters within a string are converted to lower case while respecting the current locale.
15	toLocaleUpperCase() The characters within a string are converted to upper case while respecting the current locale.
16	toLowerCase() Returns the calling string value converted to lower case.
17	toString() Returns a string representing the specified object.
18	toUpperCase() Returns the calling string value converted to uppercase.
19	valueOf() Returns the primitive value of the specified object.

String HTML Wrappers

Here is a list of the methods that return a copy of the string wrapped inside an appropriate HTML tag.

Sr.No.	Method & Description
1	anchor() Creates an HTML anchor that is used as a hypertext target.
2	big() Creates a string to be displayed in a big font as if it were in a <big> tag.
3	blink() Creates a string to blink as if it were in a <blink> tag.
4	bold() Creates a string to be displayed as bold as if it were in a <b> tag.
5	fixed() Causes a string to be displayed in fixed-pitch font as if it were in a <tt> tag
6	fontcolor() Causes a string to be displayed in the specified color as if it were in a <font color="color"> tag.
7	fontsize() Causes a string to be displayed in the specified font size as if it were in a <font size="size"> tag.
8	italics() Causes a string to be italic, as if it were in an <i> tag.
9	link() Creates an HTML hypertext link that requests another URL.
10	small() Causes a string to be displayed in a small font, as if it were in a <small> tag.
11	strike() Causes a string to be displayed as struck-out text, as if it were in a <strike> tag.
12	sub() Causes a string to be displayed as a subscript, as if it were in a <sub> tag
13	sup() Causes a string to be displayed as a superscript, as if it were in a <sup> tag

In the following sections, we will have a few examples to demonstrate the usage of String methods.