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Editor to share with you how to use the substr () method in javascript. I hope you will get something after reading this article. Let's discuss it together.

In javascript, the substr () method is used to intercept a substring of a specified length from a specified index location. It contains two parameters, the first parameter represents the starting substring of the substring to be intercepted, and the second parameter represents the intercepted length, syntax "string.substr (start,length)".

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

Substr () is used to intercept a substring of the specified length from the specified index location.

The substr () method can intercept substrings based on the specified length. It contains two parameters, the first parameter represents the starting substring of the substring to be intercepted, and the second parameter represents the length of the intercept.

Syntax format:

String.substr (start,length)

Start: required. The starting subscript of the substring to be extracted. Must be a numeric value. If it is a negative number, this parameter declares the position from the end of the string. That is,-1 represents the last character,-2 represents the penultimate character, and so on. This is useful when the left character length is not fixed.

Length: optional. The number of characters in the substring. Must be a numeric value. If this parameter is omitted, the string from the beginning to the end of the string is returned.

Return value:

A new string containing length characters starting at the start of string (including the characters referred to by start). If length is not specified, the returned string contains the characters from start to the end of string.

Example:

Gets the subscript position of the last period of the string, and then intercepts 4 characters from the following position.

Var s = "hello world! welcome to! https://www.php.cn/course/list/29.html";var b = s.substr (s.lastIndexOf (". ") + 1 console.log 4); / / intercept the four characters after the last period console.log (b); / / return the substring" html "

If the second parameter is omitted, all characters from the start position to the end are intercepted. Considering that the length of the extension is not fixed, it is more flexible to omit the second parameter.

Var b = s.substr (s.lastIndexOf (".") + 1); after reading this article, I believe you have a certain understanding of "how to use the substr () method in javascript". If you want to know more about it, welcome to follow the industry information channel, thank you for reading!

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