Introduction to 2 functions for intercepting strings in JavaScript_javascript skills

First, let’s take a look at the introduction to the use of the substring function.

1. substring

substring requires at least one parameter, the first parameter is the starting position, and the second optional parameter is the ending position.

Only one parameter:

Copy code The code is as follows:

Two parameters:

Copy code The code is as follows:

2. substr

substr also requires at least one parameter. The first parameter is the starting position, and the second parameter is optional and is the length.

Only one parameter:

Copy code The code is as follows:

Two parameters:

Copy code The code is as follows:

As can be seen from the above example, when substring and substr have only one parameter, the results are the same, and only the second parameter is different.