Common methods for intercepting strings with JS and examples of their use_javascript skills

Use substring() or slice()

Function: split()
Function: Use a specified delimiter to split a string and store it in an array
Example:

Copy code The code is as follows:

str=”jpg|bmp|gif|ico|png” ;
arr=theString.split("|");
//arr is an array containing the character values ​​"jpg", "bmp", "gif", "ico" and "png"

Function: John()
Function: Combine an array into a string using the delimiter of your choice
Example:

Copy the code The code is as follows:

var delimitedString=myArray.join(delimiter);
var myList=new Array("jpg","bmp", "gif","ico","png");
var portableList=myList.join("|");
//The result is jpg|bmp|gif|ico|png

Function: substring()
Function: String interception, for example, if you want to get "Minidx" from "MinidxSearchEngine", you need to use substring(0,6)

Function: indexOf()
Function: Return the subscript of the first character matching the substring in the string

Copy code The code is as follows:

var myString="JavaScript";
var w=myString.indexOf("v");w will be 2
var x=myString.indexOf("S");x will be 4
var y=myString.indexOf("Script");y will also be 4
var z=myString.indexOf("key");z will be -1

Continued:

1.substring method

Definition and usage
The substring method is used to extract characters between two specified subscripts in a string.

Syntax
stringObject.substring(start,stop)

Parameter Description
start Required. A nonnegative integer that specifies the position in stringObject of the first character of the substring to be extracted.
stop optional. A nonnegative integer that is one position in the stringObject that is one more than the last character of the substring to be extracted. If this parameter is omitted, the returned substring will go to the end of the string.

Return value
A new string value contains a substring of stringObject. Its content is all characters from start to stop-1, and its length is stop minus start. .

Explanation
The substring returned by the substring method includes the characters at start, but does not include the characters at end.
If start and end are equal, then this method returns an empty string (that is, a string of length 0).
If start is greater than end, then this method will swap the two parameters before extracting the substring.
If start or end is negative, then it will be replaced by 0.

2.substr method

Definition and usage
The substr method is used to return a substring of specified length starting from the specified position.

Syntax
stringObject.substr(start [, length])

Parameter Description
start Required. The starting position of the desired substring. The first character in the string has index 0.
length optional. The number of characters that should be included in the returned substring.

Description
If length is 0 or negative, an empty string will be returned.
If this parameter is not specified, the substring will be continued to the end of stringObject.

Example:

Copy code The code is as follows:

var str = "0123456789";

alert(str.substring(0));------------"0123456789"
alert(str.substring(5));------------"56789"
alert(str.substring(10));-----------""
alert(str.substring(12));-----------""
alert(str.substring(-5));-----------"0123456789"
alert(str.substring(-10));----------"0123456789"
alert(str.substring(-12));----------"0123456789"
alert(str.substring(0,5));----------"01234"
alert(str.substring(0,10));---------"0123456789"
alert(str.substring(0,12));---------"0123456789"
alert(str.substring(2,0));----------"01"
alert(str.substring(2,2));----------""
alert(str.substring(2,5));----------"234"
alert(str.substring(2,12));---------"23456789"
alert(str.substring(2,-2));---------"01"
alert(str.substring(-1,5));---------"01234"
alert(str.substring(-1,-5));--------""

alert(str.substr(0));---------------"0123456789"
alert(str.substr(5));---------------"56789"
alert(str.substr(10));--------------""
alert(str.substr(12));--------------""
alert(str.substr(-5));--------------"0123456789"
alert(str.substr(-10));-------------"0123456789"
alert(str.substr(-12));-------------"0123456789"
alert(str.substr(0,5));-------------"01234"
alert(str.substr(0,10));------------"0123456789"
alert(str.substr(0,12));------------"0123456789"
alert(str.substr(2,0));-------------""
alert(str.substr(2,2));-------------"23"
alert(str.substr(2,5));-------------"23456"
alert(str.substr(2,12));------------"23456789"
alert(str.substr(2,-2));------------""
alert(str.substr(-1,5));------------"01234"
alert(str.substr(-1,-5));-----------""