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This article mainly introduces "how to use web front-end string". In daily operation, I believe many people have doubts about how to use web front-end string. Xiaobian consulted all kinds of data and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about "how to use web front-end string". Next, please follow the editor to study!

What is a string?

A string is a string of characters enclosed in single (double) quotes. A string is a basic type of JavaScript.

● "undefined"-if this value is not defined

● "boolean"-if this value is a Boolean value

● "string"-- if this value is a string

● "number"-if this value is a numeric value

● "object"-if this value is an object or null

String operation > what's the difference from 1 "1" 2 to 1 "1" 11? (small review)

Declaration of the string:

Var str= "pro"; the basic type defines a string variable str with the content of "pro"

Var str = new String ("hello"); the reference type defines a string variable str with the content hello. Note that the variables generated with new are all variables of the reference type, also known as objects, when str is of object (object) type.

One of the JavaScript features > everything is an object

The primitive type value refers to a simple data segment, while the reference type is a point to the internal object of the javascript.

String and html

1. When the html is compiled into a string and inserted into the page, the JavaScript parser parses the string directly into code. For example: [xss_clean] ('I am bold text / strong >')

What does it look like on the page? For loop and string concatenation. (practice)

Big () displays the string in a large font

Bold () displays strings in bold

Fixed () displays the string as typewriter text

Strike () uses delete lines to display strings

Fontcolor () displays the string using the specified color

Fontsize () uses the specified size to display the string

Link () displays the string as a link

Sub () displays the string as a subscript

Sup () displays the string as superscript

/ / all of the above methods return a string with a tag added, but do not operate on the string itself

Product list page without html code

The difference between the two ways of declaring strings. Different types (reasons). Subscript length of a string

String operation >

1. Query operation

1) indexOf ("abc") finds the location where the string first appears

2) lastIndexOf ("abc") finds the location of the last occurrence of the string. If it is not found, return-1.

3) replace () replaces the string / / returns a modified string without manipulating the original string

Replace replacement string

Such as: var str= "how are you"

Alert (str.replace ("are", "old are"))

two。 Get operation

CharAt (3) / / get characters with subscript 3

CharCodeAt (3) / / gets the Unicode code of the character with subscript 3

Unicode (Unicode, Universal Code, single Code) is an industry standard in the field of computer science, including character set, coding scheme and so on. Simida, a translator

String.fromCharCode (94) / / convert encoding to characters

Because fromCharCode () is a method in the String object, use it with the prefix String

Substring (start,end) / / intercepts the string, starting at the start bit and stopping at the end bit.

Character set

GBK, GB2312, GB18030, BIG5 (traditional Chinese)

Unicode-8 UTF-8 Unicode-16

Split (separator, howmany) > splits into arrays based on delimiters and

Separator (string); / / based on what to split

Howmany (you can specify the maximum length of the returned array)

[note] if the empty string ("") is used as a separator, then each character in the stringObject is split.

3. Splicing operation

Concat () concatenate string / / the most useless method

4. Case operation

ToLowerCase ()

ToUpperCase ()

At this point, the study on "how to use web front-end strings" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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