Getting started with the substring method of JavaScript string objects (used to intercept strings)_Basic knowledge

JavaScript substring method

substring method is used to intercept a string by specifying the start and end positions and return the intercepted part of the string. Its syntax is as follows:

Tip: If the parameters start and end are equal, then this method returns an empty string. If start is greater than end, the method will swap the two parameters before intercepting the string.

substring method instance

The difference between substring, slice and substr

1.substring cannot accept negative parameters, but the slice method can
2. The second parameter of substring is to specify the end position of interception, and the second parameter of substr method is to specify the length of string interception